diff --git a/doc/manual/rl-next/json-format-changes.md b/doc/manual/rl-next/json-format-changes.md
new file mode 100644
index 000000000..c5518ee1b
--- /dev/null
+++ b/doc/manual/rl-next/json-format-changes.md
@@ -0,0 +1,47 @@
+---
+synopsis: "JSON format changes for store path info and derivations"
+prs: []
+issues: []
+---
+
+JSON formats for store path info and derivations have been updated with new versions and structured fields.
+
+## Store Path Info JSON (Version 2)
+
+The store path info JSON format has been updated from version 1 to version 2:
+
+- **Added `version` field**:
+
+  All store path info JSON now includes `"version": 2`.
+
+- **Structured `ca` field**:
+
+  Content address is now a structured JSON object instead of a string:
+
+  - Old: `"ca": "fixed:r:sha256:1abc..."`
+  - New: `"ca": {"method": "nar", "hash": {"algorithm": "sha256", "format": "base64", "hash": "EMIJ+giQ..."}}`
+  - Still `null` values for input-addressed store objects
+
+Version 1 format is still accepted when reading for backward compatibility.
+
+**Affected command**: `nix path-info --json`
+
+## Derivation JSON (Version 4)
+
+The derivation JSON format has been updated from version 3 to version 4:
+
+- **Restructured inputs**:
+
+  Inputs are now nested under an `inputs` object:
+
+  - Old: `"inputSrcs": [...], "inputDrvs": {...}`
+  - New: `"inputs": {"srcs": [...], "drvs": {...}}`
+
+- **Consistent content addresses**:
+
+  Floating content-addressed outputs now use structured JSON format.
+  This is the same format as `ca` in in store path info (after the new version).
+
+Version 3 and earlier formats are *not* accepted when reading.
+
+**Affected command**: `nix derivation`, namely it's `show` and `add` sub-commands.
diff --git a/doc/manual/source/protocols/json/derivation.md b/doc/manual/source/protocols/json/derivation.md
index a4a4ea79d..6eafb255e 100644
--- a/doc/manual/source/protocols/json/derivation.md
+++ b/doc/manual/source/protocols/json/derivation.md
@@ -1,7 +1,7 @@
-{{#include derivation-v3-fixed.md}}
+{{#include derivation-v4-fixed.md}}
 
 <!-- need to convert YAML to JSON first
 ## Raw Schema
 
-[JSON Schema for Derivation v3](schema/derivation-v3.json)
+[JSON Schema for Derivation v3](schema/derivation-v4.json)
 -->
diff --git a/doc/manual/source/protocols/json/meson.build b/doc/manual/source/protocols/json/meson.build
index c56de49c7..4ab94c63b 100644
--- a/doc/manual/source/protocols/json/meson.build
+++ b/doc/manual/source/protocols/json/meson.build
@@ -12,8 +12,8 @@ schemas = [
   'hash-v1',
   'content-address-v1',
   'store-path-v1',
-  'store-object-info-v1',
-  'derivation-v3',
+  'store-object-info-v2',
+  'derivation-v4',
   'deriving-path-v1',
   'build-trace-entry-v1',
   'build-result-v1',
diff --git a/doc/manual/source/protocols/json/schema/derivation-v3.yaml b/doc/manual/source/protocols/json/schema/derivation-v4.yaml
similarity index 78%
rename from doc/manual/source/protocols/json/schema/derivation-v3.yaml
rename to doc/manual/source/protocols/json/schema/derivation-v4.yaml
index fa68adcb1..2528f7502 100644
--- a/doc/manual/source/protocols/json/schema/derivation-v3.yaml
+++ b/doc/manual/source/protocols/json/schema/derivation-v4.yaml
@@ -1,8 +1,8 @@
 "$schema": "http://json-schema.org/draft-04/schema"
-"$id": "https://nix.dev/manual/nix/latest/protocols/json/schema/derivation-v3.json"
+"$id": "https://nix.dev/manual/nix/latest/protocols/json/schema/derivation-v4.json"
 title: Derivation
 description: |
-  Experimental JSON representation of a Nix derivation (version 3).
+  Experimental JSON representation of a Nix derivation (version 4).
 
   This schema describes the JSON representation of Nix's `Derivation` type.
 
@@ -17,8 +17,7 @@ required:
   - name
   - version
   - outputs
-  - inputSrcs
-  - inputDrvs
+  - inputs
   - system
   - builder
   - args
@@ -32,10 +31,10 @@ properties:
       Used when calculating store paths for the derivation’s outputs.
 
   version:
-    const: 3
-    title: Format version (must be 3)
+    const: 4
+    title: Format version (must be 4)
     description: |
-      Must be `3`.
+      Must be `4`.
       This is a guard that allows us to continue evolving this format.
       The choice of `3` is fairly arbitrary, but corresponds to this informal version:
 
@@ -47,6 +46,12 @@ properties:
 
       - Version 3: Drop store dir from store paths, just include base name.
 
+      - Version 4: Two cleanups, batched together to lesson churn:
+
+        - Reorganize inputs into nested structure (`inputs.srcs` and `inputs.drvs`)
+
+        - Use canonical content address JSON format for floating content addressed derivation outputs.
+
       Note that while this format is experimental, the maintenance of versions is best-effort, and not promised to identify every change.
 
   outputs:
@@ -70,47 +75,56 @@ properties:
     additionalProperties:
       "$ref": "#/$defs/output/overall"
 
-  inputSrcs:
-    type: array
-    title: Input source paths
-    description: |
-      List of store paths on which this derivation depends.
-
-      > **Example**
-      >
-      > ```json
-      > "inputSrcs": [
-      >   "47y241wqdhac3jm5l7nv0x4975mb1975-separate-debug-info.sh",
-      >   "56d0w71pjj9bdr363ym3wj1zkwyqq97j-fix-pop-var-context-error.patch"
-      > ]
-      > ```
-    items:
-      $ref: "store-path-v1.yaml"
-
-  inputDrvs:
+  inputs:
     type: object
-    title: Input derivations
+    title: Derivation inputs
     description: |
-      Mapping of derivation paths to lists of output names they provide.
-
-      > **Example**
-      >
-      > ```json
-      > "inputDrvs": {
-      >   "6lkh5yi7nlb7l6dr8fljlli5zfd9hq58-curl-7.73.0.drv": ["dev"],
-      >   "fn3kgnfzl5dzym26j8g907gq3kbm8bfh-unzip-6.0.drv": ["out"]
-      > }
-      > ```
-      >
-      > specifies that this derivation depends on the `dev` output of `curl`, and the `out` output of `unzip`.
-    patternProperties:
-      "^[0123456789abcdfghijklmnpqrsvwxyz]{32}-.+\\.drv$":
-        title: Store Path
+      Input dependencies for the derivation, organized into source paths and derivation dependencies.
+    required:
+      - srcs
+      - drvs
+    properties:
+      srcs:
+        type: array
+        title: Input source paths
         description: |
-          A store path to a derivation, mapped to the outputs of that derivation.
-        oneOf:
-        - "$ref": "#/$defs/outputNames"
-        - "$ref": "#/$defs/dynamicOutputs"
+          List of store paths on which this derivation depends.
+
+          > **Example**
+          >
+          > ```json
+          > "srcs": [
+          >   "47y241wqdhac3jm5l7nv0x4975mb1975-separate-debug-info.sh",
+          >   "56d0w71pjj9bdr363ym3wj1zkwyqq97j-fix-pop-var-context-error.patch"
+          > ]
+          > ```
+        items:
+          $ref: "store-path-v1.yaml"
+      drvs:
+        type: object
+        title: Input derivations
+        description: |
+          Mapping of derivation paths to lists of output names they provide.
+
+          > **Example**
+          >
+          > ```json
+          > "drvs": {
+          >   "6lkh5yi7nlb7l6dr8fljlli5zfd9hq58-curl-7.73.0.drv": ["dev"],
+          >   "fn3kgnfzl5dzym26j8g907gq3kbm8bfh-unzip-6.0.drv": ["out"]
+          > }
+          > ```
+          >
+          > specifies that this derivation depends on the `dev` output of `curl`, and the `out` output of `unzip`.
+        patternProperties:
+          "^[0123456789abcdfghijklmnpqrsvwxyz]{32}-.+\\.drv$":
+            title: Store Path
+            description: |
+              A store path to a derivation, mapped to the outputs of that derivation.
+            oneOf:
+            - "$ref": "#/$defs/outputNames"
+            - "$ref": "#/$defs/dynamicOutputs"
+        additionalProperties: false
     additionalProperties: false
 
   system:
@@ -189,24 +203,18 @@ properties:
         The output is content-addressed, and the content-address is fixed in advance.
 
         See [Fixed-output content-addressing](@docroot@/store/derivation/outputs/content-address.md#fixed) for more details.
-      type: object
+      "$ref": "./content-address-v1.yaml"
       required:
         - method
-        - hashAlgo
         - hash
       properties:
         method:
-          "$ref": "./content-address-v1.yaml#/$defs/method"
           description: |
             Method of content addressing used for this output.
-        hashAlgo:
-          title: Hash algorithm
-          "$ref": "./hash-v1.yaml#/$defs/algorithm"
         hash:
-          type: string
           title: Expected hash value
           description: |
-            The expected content hash in base-16.
+            The expected content hash.
       additionalProperties: false
 
     caFloating:
diff --git a/doc/manual/source/protocols/json/schema/store-object-info-v1 b/doc/manual/source/protocols/json/schema/store-object-info-v2
similarity index 100%
rename from doc/manual/source/protocols/json/schema/store-object-info-v1
rename to doc/manual/source/protocols/json/schema/store-object-info-v2
diff --git a/doc/manual/source/protocols/json/schema/store-object-info-v1.yaml b/doc/manual/source/protocols/json/schema/store-object-info-v2.yaml
similarity index 91%
rename from doc/manual/source/protocols/json/schema/store-object-info-v1.yaml
rename to doc/manual/source/protocols/json/schema/store-object-info-v2.yaml
index d79f25043..4f442e0c3 100644
--- a/doc/manual/source/protocols/json/schema/store-object-info-v1.yaml
+++ b/doc/manual/source/protocols/json/schema/store-object-info-v2.yaml
@@ -1,6 +1,6 @@
-"$schema": "http://json-schema.org/draft-07/schema"
-"$id": "https://nix.dev/manual/nix/latest/protocols/json/schema/store-object-info-v1.json"
-title: Store Object Info
+"$schema": "http://json-schema.org/draft-04/schema"
+"$id": "https://nix.dev/manual/nix/latest/protocols/json/schema/store-object-info-v2.json"
+title: Store Object Info v2
 description: |
   Information about a [store object](@docroot@/store/store-object.md).
 
@@ -41,11 +41,27 @@ $defs:
       This is the minimal set of fields that describe what a store object contains.
     type: object
     required:
+      - version
       - narHash
       - narSize
       - references
       - ca
     properties:
+      version:
+        type: integer
+        const: 2
+        title: Format version (must be 2)
+        description: |
+          Must be `2`.
+          This is a guard that allows us to continue evolving this format.
+          Here is the rough version history:
+
+          - Version 0: `.narinfo` line-oriented format
+
+          - Version 1: Original JSON format, with ugly `"r:sha256"` inherited from `.narinfo` format.
+
+          - Version 2: Use structured JSON type for `ca`
+
       path:
         type: string
         title: Store Path
@@ -76,7 +92,10 @@ $defs:
           type: string
 
       ca:
-        type: ["string", "null"]
+        oneOf:
+          - type: "null"
+            const: null
+          - "$ref": "./content-address-v1.yaml"
         title: Content Address
         description: |
           If the store object is [content-addressed](@docroot@/store/store-object/content-address.md),
@@ -91,6 +110,7 @@ $defs:
       In other words, the same store object in different stores could have different values for these impure fields.
     type: object
     required:
+      - version
       - narHash
       - narSize
       - references
@@ -101,6 +121,7 @@ $defs:
       - ultimate
       - signatures
     properties:
+      version: { $ref: "#/$defs/base/properties/version" }
       path: { $ref: "#/$defs/base/properties/path" }
       narHash: { $ref: "#/$defs/base/properties/narHash" }
       narSize: { $ref: "#/$defs/base/properties/narSize" }
@@ -164,6 +185,7 @@ $defs:
       This download information, being specific to how the store object happens to be stored and transferred, is also considered to be non-intrinsic / impure.
     type: object
     required:
+      - version
       - narHash
       - narSize
       - references
@@ -179,6 +201,7 @@ $defs:
       - downloadHash
       - downloadSize
     properties:
+      version: { $ref: "#/$defs/base/properties/version" }
       path: { $ref: "#/$defs/base/properties/path" }
       narHash: { $ref: "#/$defs/base/properties/narHash" }
       narSize: { $ref: "#/$defs/base/properties/narSize" }
diff --git a/doc/manual/source/protocols/json/store-object-info.md b/doc/manual/source/protocols/json/store-object-info.md
index 4673dd773..6a101ab0f 100644
--- a/doc/manual/source/protocols/json/store-object-info.md
+++ b/doc/manual/source/protocols/json/store-object-info.md
@@ -1,29 +1,29 @@
-{{#include store-object-info-v1-fixed.md}}
+{{#include store-object-info-v2-fixed.md}}
 
 ## Examples
 
 ### Minimal store object (content-addressed)
 
 ```json
-{{#include schema/store-object-info-v1/pure.json}}
+{{#include schema/store-object-info-v2/pure.json}}
 ```
 
 ### Store object with impure fields
 
 ```json
-{{#include schema/store-object-info-v1/impure.json}}
+{{#include schema/store-object-info-v2/impure.json}}
 ```
 
 ### Minimal store object (empty)
 
 ```json
-{{#include schema/store-object-info-v1/empty_pure.json}}
+{{#include schema/store-object-info-v2/empty_pure.json}}
 ```
 
 ### Store object with all impure fields
 
 ```json
-{{#include schema/store-object-info-v1/empty_impure.json}}
+{{#include schema/store-object-info-v2/empty_impure.json}}
 ```
 
 ### NAR info (minimal)
@@ -41,5 +41,5 @@
 <!-- need to convert YAML to JSON first
 ## Raw Schema
 
-[JSON Schema for Store Object Info v1](schema/store-object-info-v1.json)
+[JSON Schema for Store Object Info v1](schema/store-object-info-v2.json)
 -->
diff --git a/src/json-schema-checks/meson.build b/src/json-schema-checks/meson.build
index 65a2651b7..f72affb0b 100644
--- a/src/json-schema-checks/meson.build
+++ b/src/json-schema-checks/meson.build
@@ -70,7 +70,7 @@ schemas += [
   # Match overall
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml',
+    'schema' : schema_dir / 'derivation-v4.yaml',
     'files' : [
       'dyn-dep-derivation.json',
       'simple-derivation.json',
@@ -78,7 +78,7 @@ schemas += [
   },
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml#/$defs/output/overall',
+    'schema' : schema_dir / 'derivation-v4.yaml#/$defs/output/overall',
     'files' : [
       'output-caFixedFlat.json',
       'output-caFixedNAR.json',
@@ -92,14 +92,14 @@ schemas += [
   # Match exact variant
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml#/$defs/output/inputAddressed',
+    'schema' : schema_dir / 'derivation-v4.yaml#/$defs/output/inputAddressed',
     'files' : [
       'output-inputAddressed.json',
     ],
   },
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml#/$defs/output/caFixed',
+    'schema' : schema_dir / 'derivation-v4.yaml#/$defs/output/caFixed',
     'files' : [
       'output-caFixedFlat.json',
       'output-caFixedNAR.json',
@@ -108,21 +108,21 @@ schemas += [
   },
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml#/$defs/output/caFloating',
+    'schema' : schema_dir / 'derivation-v4.yaml#/$defs/output/caFloating',
     'files' : [
       'output-caFloating.json',
     ],
   },
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml#/$defs/output/deferred',
+    'schema' : schema_dir / 'derivation-v4.yaml#/$defs/output/deferred',
     'files' : [
       'output-deferred.json',
     ],
   },
   {
     'stem' : 'derivation',
-    'schema' : schema_dir / 'derivation-v3.yaml#/$defs/output/impure',
+    'schema' : schema_dir / 'derivation-v4.yaml#/$defs/output/impure',
     'files' : [
       'output-impure.json',
     ],
@@ -134,7 +134,7 @@ schemas += [
   # Match overall
   {
     'stem' : 'store-object-info',
-    'schema' : schema_dir / 'store-object-info-v1.yaml',
+    'schema' : schema_dir / 'store-object-info-v2.yaml',
     'files' : [
       'pure.json',
       'impure.json',
@@ -144,7 +144,7 @@ schemas += [
   },
   {
     'stem' : 'nar-info',
-    'schema' : schema_dir / 'store-object-info-v1.yaml',
+    'schema' : schema_dir / 'store-object-info-v2.yaml',
     'files' : [
       'pure.json',
       'impure.json',
@@ -162,7 +162,7 @@ schemas += [
   # Match exact variant
   {
     'stem' : 'store-object-info',
-    'schema' : schema_dir / 'store-object-info-v1.yaml#/$defs/base',
+    'schema' : schema_dir / 'store-object-info-v2.yaml#/$defs/base',
     'files' : [
       'pure.json',
       'empty_pure.json',
@@ -170,7 +170,7 @@ schemas += [
   },
   {
     'stem' : 'store-object-info',
-    'schema' : schema_dir / 'store-object-info-v1.yaml#/$defs/impure',
+    'schema' : schema_dir / 'store-object-info-v2.yaml#/$defs/impure',
     'files' : [
       'impure.json',
       'empty_impure.json',
@@ -178,14 +178,14 @@ schemas += [
   },
   {
     'stem' : 'nar-info',
-    'schema' : schema_dir / 'store-object-info-v1.yaml#/$defs/base',
+    'schema' : schema_dir / 'store-object-info-v2.yaml#/$defs/base',
     'files' : [
       'pure.json',
     ],
   },
   {
     'stem' : 'nar-info',
-    'schema' : schema_dir / 'store-object-info-v1.yaml#/$defs/narInfo',
+    'schema' : schema_dir / 'store-object-info-v2.yaml#/$defs/narInfo',
     'files' : [
       'impure.json',
     ],
diff --git a/src/libstore-tests/data/derivation/ca/advanced-attributes-defaults.json b/src/libstore-tests/data/derivation/ca/advanced-attributes-defaults.json
index eb4bd4f3d..781b4cb14 100644
--- a/src/libstore-tests/data/derivation/ca/advanced-attributes-defaults.json
+++ b/src/libstore-tests/data/derivation/ca/advanced-attributes-defaults.json
@@ -12,8 +12,10 @@
     "outputHashMode": "recursive",
     "system": "my-system"
   },
-  "inputDrvs": {},
-  "inputSrcs": [],
+  "inputs": {
+    "drvs": {},
+    "srcs": []
+  },
   "name": "advanced-attributes-defaults",
   "outputs": {
     "out": {
@@ -22,5 +24,5 @@
     }
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs-defaults.json b/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs-defaults.json
index 3a4a3079b..7437b51ef 100644
--- a/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs-defaults.json
+++ b/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs-defaults.json
@@ -8,8 +8,10 @@
     "dev": "/02qcpld1y6xhs5gz9bchpxaw0xdhmsp5dv88lh25r2ss44kh8dxz",
     "out": "/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9"
   },
-  "inputDrvs": {},
-  "inputSrcs": [],
+  "inputs": {
+    "drvs": {},
+    "srcs": []
+  },
   "name": "advanced-attributes-structured-attrs-defaults",
   "outputs": {
     "dev": {
@@ -33,5 +35,5 @@
     "system": "my-system"
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs.json b/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs.json
index b10355af7..2a4e70558 100644
--- a/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs.json
+++ b/src/libstore-tests/data/derivation/ca/advanced-attributes-structured-attrs.json
@@ -9,25 +9,27 @@
     "dev": "/02qcpld1y6xhs5gz9bchpxaw0xdhmsp5dv88lh25r2ss44kh8dxz",
     "out": "/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9"
   },
-  "inputDrvs": {
-    "j56sf12rxpcv5swr14vsjn5cwm6bj03h-foo.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
+  "inputs": {
+    "drvs": {
+      "j56sf12rxpcv5swr14vsjn5cwm6bj03h-foo.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      },
+      "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      }
     },
-    "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
-    }
+    "srcs": [
+      "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv"
+    ]
   },
-  "inputSrcs": [
-    "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv"
-  ],
   "name": "advanced-attributes-structured-attrs",
   "outputs": {
     "bin": {
@@ -101,5 +103,5 @@
     "system": "my-system"
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ca/advanced-attributes.json b/src/libstore-tests/data/derivation/ca/advanced-attributes.json
index d66882036..55dbe62e0 100644
--- a/src/libstore-tests/data/derivation/ca/advanced-attributes.json
+++ b/src/libstore-tests/data/derivation/ca/advanced-attributes.json
@@ -25,25 +25,27 @@
     "requiredSystemFeatures": "rainbow uid-range",
     "system": "my-system"
   },
-  "inputDrvs": {
-    "j56sf12rxpcv5swr14vsjn5cwm6bj03h-foo.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
+  "inputs": {
+    "drvs": {
+      "j56sf12rxpcv5swr14vsjn5cwm6bj03h-foo.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      },
+      "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      }
     },
-    "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
-    }
+    "srcs": [
+      "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv"
+    ]
   },
-  "inputSrcs": [
-    "qnml92yh97a6fbrs2m5qg5cqlc8vni58-bar.drv"
-  ],
   "name": "advanced-attributes",
   "outputs": {
     "out": {
@@ -52,5 +54,5 @@
     }
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ca/self-contained.json b/src/libstore-tests/data/derivation/ca/self-contained.json
index 331beb7be..c05710140 100644
--- a/src/libstore-tests/data/derivation/ca/self-contained.json
+++ b/src/libstore-tests/data/derivation/ca/self-contained.json
@@ -10,8 +10,10 @@
     "out": "/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9",
     "system": "x86_64-linux"
   },
-  "inputDrvs": {},
-  "inputSrcs": [],
+  "inputs": {
+    "drvs": {},
+    "srcs": []
+  },
   "name": "myname",
   "outputs": {
     "out": {
@@ -20,5 +22,5 @@
     }
   },
   "system": "x86_64-linux",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/dyn-dep-derivation.json b/src/libstore-tests/data/derivation/dyn-dep-derivation.json
index 1a9f54c53..1793c5f2d 100644
--- a/src/libstore-tests/data/derivation/dyn-dep-derivation.json
+++ b/src/libstore-tests/data/derivation/dyn-dep-derivation.json
@@ -7,33 +7,35 @@
   "env": {
     "BIG_BAD": "WOLF"
   },
-  "inputDrvs": {
-    "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
-      "dynamicOutputs": {
-        "cat": {
-          "dynamicOutputs": {},
-          "outputs": [
-            "kitten"
-          ]
+  "inputs": {
+    "drvs": {
+      "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
+        "dynamicOutputs": {
+          "cat": {
+            "dynamicOutputs": {},
+            "outputs": [
+              "kitten"
+            ]
+          },
+          "goose": {
+            "dynamicOutputs": {},
+            "outputs": [
+              "gosling"
+            ]
+          }
         },
-        "goose": {
-          "dynamicOutputs": {},
-          "outputs": [
-            "gosling"
-          ]
-        }
-      },
-      "outputs": [
-        "cat",
-        "dog"
-      ]
-    }
+        "outputs": [
+          "cat",
+          "dog"
+        ]
+      }
+    },
+    "srcs": [
+      "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
+    ]
   },
-  "inputSrcs": [
-    "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
-  ],
   "name": "dyn-dep-derivation",
   "outputs": {},
   "system": "wasm-sel4",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ia/advanced-attributes-defaults.json b/src/libstore-tests/data/derivation/ia/advanced-attributes-defaults.json
index 0fa543f21..898762123 100644
--- a/src/libstore-tests/data/derivation/ia/advanced-attributes-defaults.json
+++ b/src/libstore-tests/data/derivation/ia/advanced-attributes-defaults.json
@@ -10,8 +10,10 @@
     "out": "/nix/store/1qsc7svv43m4dw2prh6mvyf7cai5czji-advanced-attributes-defaults",
     "system": "my-system"
   },
-  "inputDrvs": {},
-  "inputSrcs": [],
+  "inputs": {
+    "drvs": {},
+    "srcs": []
+  },
   "name": "advanced-attributes-defaults",
   "outputs": {
     "out": {
@@ -19,5 +21,5 @@
     }
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs-defaults.json b/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs-defaults.json
index e02392ea1..c51095986 100644
--- a/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs-defaults.json
+++ b/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs-defaults.json
@@ -8,8 +8,10 @@
     "dev": "/nix/store/8bazivnbipbyi569623skw5zm91z6kc2-advanced-attributes-structured-attrs-defaults-dev",
     "out": "/nix/store/f8f8nvnx32bxvyxyx2ff7akbvwhwd9dw-advanced-attributes-structured-attrs-defaults"
   },
-  "inputDrvs": {},
-  "inputSrcs": [],
+  "inputs": {
+    "drvs": {},
+    "srcs": []
+  },
   "name": "advanced-attributes-structured-attrs-defaults",
   "outputs": {
     "dev": {
@@ -29,5 +31,5 @@
     "system": "my-system"
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs.json b/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs.json
index 9230b06b6..e07d1294b 100644
--- a/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs.json
+++ b/src/libstore-tests/data/derivation/ia/advanced-attributes-structured-attrs.json
@@ -9,25 +9,27 @@
     "dev": "/nix/store/wyfgwsdi8rs851wmy1xfzdxy7y5vrg5l-advanced-attributes-structured-attrs-dev",
     "out": "/nix/store/7cxy4zx1vqc885r4jl2l64pymqbdmhii-advanced-attributes-structured-attrs"
   },
-  "inputDrvs": {
-    "afc3vbjbzql750v2lp8gxgaxsajphzih-foo.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
+  "inputs": {
+    "drvs": {
+      "afc3vbjbzql750v2lp8gxgaxsajphzih-foo.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      },
+      "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      }
     },
-    "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
-    }
+    "srcs": [
+      "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv"
+    ]
   },
-  "inputSrcs": [
-    "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv"
-  ],
   "name": "advanced-attributes-structured-attrs",
   "outputs": {
     "bin": {
@@ -96,5 +98,5 @@
     "system": "my-system"
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/ia/advanced-attributes.json b/src/libstore-tests/data/derivation/ia/advanced-attributes.json
index ba5911c91..372b4fbb9 100644
--- a/src/libstore-tests/data/derivation/ia/advanced-attributes.json
+++ b/src/libstore-tests/data/derivation/ia/advanced-attributes.json
@@ -23,25 +23,27 @@
     "requiredSystemFeatures": "rainbow uid-range",
     "system": "my-system"
   },
-  "inputDrvs": {
-    "afc3vbjbzql750v2lp8gxgaxsajphzih-foo.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
+  "inputs": {
+    "drvs": {
+      "afc3vbjbzql750v2lp8gxgaxsajphzih-foo.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      },
+      "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "dev",
+          "out"
+        ]
+      }
     },
-    "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "dev",
-        "out"
-      ]
-    }
+    "srcs": [
+      "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv"
+    ]
   },
-  "inputSrcs": [
-    "vj2i49jm2868j2fmqvxm70vlzmzvgv14-bar.drv"
-  ],
   "name": "advanced-attributes",
   "outputs": {
     "out": {
@@ -49,5 +51,5 @@
     }
   },
   "system": "my-system",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/derivation/output-caFixedFlat.json b/src/libstore-tests/data/derivation/output-caFixedFlat.json
index e6a0123f6..9a38608b3 100644
--- a/src/libstore-tests/data/derivation/output-caFixedFlat.json
+++ b/src/libstore-tests/data/derivation/output-caFixedFlat.json
@@ -1,5 +1,8 @@
 {
-  "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
-  "hashAlgo": "sha256",
+  "hash": {
+    "algorithm": "sha256",
+    "format": "base64",
+    "hash": "iUUXyRY8iW7DGirb0zwGgf1fRbLA7wimTJKgP7l/OQ8="
+  },
   "method": "flat"
 }
diff --git a/src/libstore-tests/data/derivation/output-caFixedNAR.json b/src/libstore-tests/data/derivation/output-caFixedNAR.json
index b57e065a9..767c605a3 100644
--- a/src/libstore-tests/data/derivation/output-caFixedNAR.json
+++ b/src/libstore-tests/data/derivation/output-caFixedNAR.json
@@ -1,5 +1,8 @@
 {
-  "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
-  "hashAlgo": "sha256",
+  "hash": {
+    "algorithm": "sha256",
+    "format": "base64",
+    "hash": "iUUXyRY8iW7DGirb0zwGgf1fRbLA7wimTJKgP7l/OQ8="
+  },
   "method": "nar"
 }
diff --git a/src/libstore-tests/data/derivation/output-caFixedText.json b/src/libstore-tests/data/derivation/output-caFixedText.json
index 84778509e..a04f1ff2a 100644
--- a/src/libstore-tests/data/derivation/output-caFixedText.json
+++ b/src/libstore-tests/data/derivation/output-caFixedText.json
@@ -1,5 +1,8 @@
 {
-  "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
-  "hashAlgo": "sha256",
+  "hash": {
+    "algorithm": "sha256",
+    "format": "base64",
+    "hash": "iUUXyRY8iW7DGirb0zwGgf1fRbLA7wimTJKgP7l/OQ8="
+  },
   "method": "text"
 }
diff --git a/src/libstore-tests/data/derivation/simple-derivation.json b/src/libstore-tests/data/derivation/simple-derivation.json
index 41a049aef..04129a096 100644
--- a/src/libstore-tests/data/derivation/simple-derivation.json
+++ b/src/libstore-tests/data/derivation/simple-derivation.json
@@ -7,20 +7,22 @@
   "env": {
     "BIG_BAD": "WOLF"
   },
-  "inputDrvs": {
-    "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
-      "dynamicOutputs": {},
-      "outputs": [
-        "cat",
-        "dog"
-      ]
-    }
+  "inputs": {
+    "drvs": {
+      "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
+        "dynamicOutputs": {},
+        "outputs": [
+          "cat",
+          "dog"
+        ]
+      }
+    },
+    "srcs": [
+      "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
+    ]
   },
-  "inputSrcs": [
-    "c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
-  ],
   "name": "simple-derivation",
   "outputs": {},
   "system": "wasm-sel4",
-  "version": 3
+  "version": 4
 }
diff --git a/src/libstore-tests/data/nar-info/impure.json b/src/libstore-tests/data/nar-info/impure.json
index bb9791a6a..f35ff990b 100644
--- a/src/libstore-tests/data/nar-info/impure.json
+++ b/src/libstore-tests/data/nar-info/impure.json
@@ -1,5 +1,12 @@
 {
-  "ca": "fixed:r:sha256:1lr187v6dck1rjh2j6svpikcfz53wyl3qrlcbb405zlh13x0khhh",
+  "ca": {
+    "hash": {
+      "algorithm": "sha256",
+      "format": "base64",
+      "hash": "EMIJ+giQ/gLIWoxmPKjno3zHZrxbGymgzGGyZvZBIdM="
+    },
+    "method": "nar"
+  },
   "compression": "xz",
   "deriver": "/nix/store/g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
   "downloadHash": "sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc=",
@@ -16,5 +23,6 @@
     "qwer"
   ],
   "ultimate": true,
-  "url": "nar/1w1fff338fvdw53sqgamddn1b2xgds473pv6y13gizdbqjv4i5p3.nar.xz"
+  "url": "nar/1w1fff338fvdw53sqgamddn1b2xgds473pv6y13gizdbqjv4i5p3.nar.xz",
+  "version": 2
 }
diff --git a/src/libstore-tests/data/nar-info/pure.json b/src/libstore-tests/data/nar-info/pure.json
index 955baec31..2c5cb3bde 100644
--- a/src/libstore-tests/data/nar-info/pure.json
+++ b/src/libstore-tests/data/nar-info/pure.json
@@ -1,9 +1,17 @@
 {
-  "ca": "fixed:r:sha256:1lr187v6dck1rjh2j6svpikcfz53wyl3qrlcbb405zlh13x0khhh",
+  "ca": {
+    "hash": {
+      "algorithm": "sha256",
+      "format": "base64",
+      "hash": "EMIJ+giQ/gLIWoxmPKjno3zHZrxbGymgzGGyZvZBIdM="
+    },
+    "method": "nar"
+  },
   "narHash": "sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc=",
   "narSize": 34878,
   "references": [
     "/nix/store/g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
     "/nix/store/n5wkd9frr45pa74if5gpz9j7mifg27fh-foo"
-  ]
+  ],
+  "version": 2
 }
diff --git a/src/libstore-tests/data/path-info/empty_impure.json b/src/libstore-tests/data/path-info/empty_impure.json
index be982dcef..381acaa03 100644
--- a/src/libstore-tests/data/path-info/empty_impure.json
+++ b/src/libstore-tests/data/path-info/empty_impure.json
@@ -6,5 +6,6 @@
   "references": [],
   "registrationTime": null,
   "signatures": [],
-  "ultimate": false
+  "ultimate": false,
+  "version": 2
 }
diff --git a/src/libstore-tests/data/path-info/empty_pure.json b/src/libstore-tests/data/path-info/empty_pure.json
index 10d9f508a..6d3fa646b 100644
--- a/src/libstore-tests/data/path-info/empty_pure.json
+++ b/src/libstore-tests/data/path-info/empty_pure.json
@@ -2,5 +2,6 @@
   "ca": null,
   "narHash": "sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc=",
   "narSize": 0,
-  "references": []
+  "references": [],
+  "version": 2
 }
diff --git a/src/libstore-tests/data/path-info/impure.json b/src/libstore-tests/data/path-info/impure.json
index 0c452cc49..141b38a16 100644
--- a/src/libstore-tests/data/path-info/impure.json
+++ b/src/libstore-tests/data/path-info/impure.json
@@ -1,5 +1,12 @@
 {
-  "ca": "fixed:r:sha256:1lr187v6dck1rjh2j6svpikcfz53wyl3qrlcbb405zlh13x0khhh",
+  "ca": {
+    "hash": {
+      "algorithm": "sha256",
+      "format": "base64",
+      "hash": "EMIJ+giQ/gLIWoxmPKjno3zHZrxbGymgzGGyZvZBIdM="
+    },
+    "method": "nar"
+  },
   "deriver": "/nix/store/g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar.drv",
   "narHash": "sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc=",
   "narSize": 34878,
@@ -12,5 +19,6 @@
     "asdf",
     "qwer"
   ],
-  "ultimate": true
+  "ultimate": true,
+  "version": 2
 }
diff --git a/src/libstore-tests/data/path-info/pure.json b/src/libstore-tests/data/path-info/pure.json
index 955baec31..2c5cb3bde 100644
--- a/src/libstore-tests/data/path-info/pure.json
+++ b/src/libstore-tests/data/path-info/pure.json
@@ -1,9 +1,17 @@
 {
-  "ca": "fixed:r:sha256:1lr187v6dck1rjh2j6svpikcfz53wyl3qrlcbb405zlh13x0khhh",
+  "ca": {
+    "hash": {
+      "algorithm": "sha256",
+      "format": "base64",
+      "hash": "EMIJ+giQ/gLIWoxmPKjno3zHZrxbGymgzGGyZvZBIdM="
+    },
+    "method": "nar"
+  },
   "narHash": "sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc=",
   "narSize": 34878,
   "references": [
     "/nix/store/g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
     "/nix/store/n5wkd9frr45pa74if5gpz9j7mifg27fh-foo"
-  ]
+  ],
+  "version": 2
 }
diff --git a/src/libstore-tests/nix_api_store.cc b/src/libstore-tests/nix_api_store.cc
index 228b8069f..bf411053a 100644
--- a/src/libstore-tests/nix_api_store.cc
+++ b/src/libstore-tests/nix_api_store.cc
@@ -636,7 +636,7 @@ TEST_F(NixApiStoreTestWithRealisedPath, nix_store_realise_output_ordering)
     auto outj_ph = nix::hashPlaceholder("outj");
 
     std::string drvJson = R"({
-        "version": 3,
+        "version": 4,
         "name": "multi-output-test",
         "system": ")" + nix::settings.thisSystem.get()
                           + R"(",
@@ -668,8 +668,10 @@ TEST_F(NixApiStoreTestWithRealisedPath, nix_store_realise_output_ordering)
             "outa": ")" + outa_ph
                           + R"("
         },
-        "inputDrvs": {},
-        "inputSrcs": [],
+        "inputs": {
+          "drvs": {},
+          "srcs": []
+        },
         "outputs": {
             "outd": { "hashAlgo": "sha256", "method": "nar" },
             "outf": { "hashAlgo": "sha256", "method": "nar" },
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index e6ac08fd9..31ca167f9 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -1293,15 +1293,13 @@ void adl_serializer<DerivationOutput>::to_json(json & res, const DerivationOutpu
         overloaded{
             [&](const DerivationOutput::InputAddressed & doi) { res["path"] = doi.path; },
             [&](const DerivationOutput::CAFixed & dof) {
-    /* it would be nice to output the path for user convenience, but
-       this would require us to know the store dir. */
+                res = dof.ca;
+        // FIXME print refs?
+        /* it would be nice to output the path for user convenience, but
+           this would require us to know the store dir. */
 #if 0
                 res["path"] = dof.path(store, drvName, outputName);
 #endif
-                res["method"] = std::string{dof.ca.method.render()};
-                res["hashAlgo"] = printHashAlgo(dof.ca.hash.algo);
-                res["hash"] = dof.ca.hash.to_string(HashFormat::Base16, false);
-                // FIXME print refs?
             },
             [&](const DerivationOutput::CAFloating & dof) {
                 res["method"] = std::string{dof.method.render()};
@@ -1341,15 +1339,12 @@ adl_serializer<DerivationOutput>::from_json(const json & _json, const Experiment
         };
     }
 
-    else if (keys == (std::set<std::string_view>{"method", "hashAlgo", "hash"})) {
-        auto [method, hashAlgo] = methodAlgo();
+    else if (keys == (std::set<std::string_view>{"method", "hash"})) {
         auto dof = DerivationOutput::CAFixed{
-            .ca =
-                ContentAddress{
-                    .method = std::move(method),
-                    .hash = Hash::parseNonSRIUnprefixed(getString(valueAt(json, "hash")), hashAlgo),
-                },
+            .ca = static_cast<ContentAddress>(_json),
         };
+        if (dof.ca.method == ContentAddressMethod::Raw::Text)
+            xpSettings.require(Xp::DynamicDerivations, "text-hashed derivation output in JSON");
         /* We no longer produce this (denormalized) field (for the
            reasons described above), so we don't need to check it. */
 #if 0
@@ -1392,7 +1387,7 @@ void adl_serializer<Derivation>::to_json(json & res, const Derivation & d)
 
     res["name"] = d.name;
 
-    res["version"] = 3;
+    res["version"] = 4;
 
     {
         nlohmann::json & outputsObj = res["outputs"];
@@ -1403,13 +1398,16 @@ void adl_serializer<Derivation>::to_json(json & res, const Derivation & d)
     }
 
     {
-        auto & inputsList = res["inputSrcs"];
-        inputsList = nlohmann::json::array();
-        for (auto & input : d.inputSrcs)
-            inputsList.emplace_back(input);
-    }
+        auto & inputsObj = res["inputs"];
+        inputsObj = nlohmann::json::object();
+
+        {
+            auto & inputsList = inputsObj["srcs"];
+            inputsList = nlohmann::json::array();
+            for (auto & input : d.inputSrcs)
+                inputsList.emplace_back(input);
+        }
 
-    {
         auto doInput = [&](this const auto & doInput, const auto & inputNode) -> nlohmann::json {
             auto value = nlohmann::json::object();
             value["outputs"] = inputNode.value;
@@ -1421,12 +1419,11 @@ void adl_serializer<Derivation>::to_json(json & res, const Derivation & d)
             }
             return value;
         };
-        {
-            auto & inputDrvsObj = res["inputDrvs"];
-            inputDrvsObj = nlohmann::json::object();
-            for (auto & [inputDrv, inputNode] : d.inputDrvs.map) {
-                inputDrvsObj[inputDrv.to_string()] = doInput(inputNode);
-            }
+
+        auto & inputDrvsObj = inputsObj["drvs"];
+        inputDrvsObj = nlohmann::json::object();
+        for (auto & [inputDrv, inputNode] : d.inputDrvs.map) {
+            inputDrvsObj[inputDrv.to_string()] = doInput(inputNode);
         }
     }
 
@@ -1449,8 +1446,8 @@ Derivation adl_serializer<Derivation>::from_json(const json & _json, const Exper
 
     res.name = getString(valueAt(json, "name"));
 
-    if (valueAt(json, "version") != 3)
-        throw Error("Only derivation format version 3 is currently supported.");
+    if (valueAt(json, "version") != 4)
+        throw Error("Only derivation format version 4 is currently supported.");
 
     try {
         auto outputs = getObject(valueAt(json, "outputs"));
@@ -1463,32 +1460,39 @@ Derivation adl_serializer<Derivation>::from_json(const json & _json, const Exper
     }
 
     try {
-        auto inputSrcs = getArray(valueAt(json, "inputSrcs"));
-        for (auto & input : inputSrcs)
-            res.inputSrcs.insert(input);
-    } catch (Error & e) {
-        e.addTrace({}, "while reading key 'inputSrcs'");
-        throw;
-    }
+        auto inputsObj = getObject(valueAt(json, "inputs"));
 
-    try {
-        auto doInput = [&](this const auto & doInput, const auto & _json) -> DerivedPathMap<StringSet>::ChildNode {
-            auto & json = getObject(_json);
-            DerivedPathMap<StringSet>::ChildNode node;
-            node.value = getStringSet(valueAt(json, "outputs"));
-            auto drvs = getObject(valueAt(json, "dynamicOutputs"));
-            for (auto & [outputId, childNode] : drvs) {
-                xpSettings.require(
-                    Xp::DynamicDerivations, [&] { return fmt("dynamic output '%s' in JSON", outputId); });
-                node.childMap[outputId] = doInput(childNode);
-            }
-            return node;
-        };
-        auto drvs = getObject(valueAt(json, "inputDrvs"));
-        for (auto & [inputDrvPath, inputOutputs] : drvs)
-            res.inputDrvs.map[StorePath{inputDrvPath}] = doInput(inputOutputs);
+        try {
+            auto inputSrcs = getArray(valueAt(inputsObj, "srcs"));
+            for (auto & input : inputSrcs)
+                res.inputSrcs.insert(input);
+        } catch (Error & e) {
+            e.addTrace({}, "while reading key 'srcs'");
+            throw;
+        }
+
+        try {
+            auto doInput = [&](this const auto & doInput, const auto & _json) -> DerivedPathMap<StringSet>::ChildNode {
+                auto & json = getObject(_json);
+                DerivedPathMap<StringSet>::ChildNode node;
+                node.value = getStringSet(valueAt(json, "outputs"));
+                auto drvs = getObject(valueAt(json, "dynamicOutputs"));
+                for (auto & [outputId, childNode] : drvs) {
+                    xpSettings.require(
+                        Xp::DynamicDerivations, [&] { return fmt("dynamic output '%s' in JSON", outputId); });
+                    node.childMap[outputId] = doInput(childNode);
+                }
+                return node;
+            };
+            auto drvs = getObject(valueAt(inputsObj, "drvs"));
+            for (auto & [inputDrvPath, inputOutputs] : drvs)
+                res.inputDrvs.map[StorePath{inputDrvPath}] = doInput(inputOutputs);
+        } catch (Error & e) {
+            e.addTrace({}, "while reading key 'drvs'");
+            throw;
+        }
     } catch (Error & e) {
-        e.addTrace({}, "while reading key 'inputDrvs'");
+        e.addTrace({}, "while reading key 'inputs'");
         throw;
     }
 
diff --git a/src/libstore/path-info.cc b/src/libstore/path-info.cc
index 09a78a4ad..c535d08f4 100644
--- a/src/libstore/path-info.cc
+++ b/src/libstore/path-info.cc
@@ -156,6 +156,8 @@ UnkeyedValidPathInfo::toJSON(const StoreDirConfig & store, bool includeImpureInf
 
     auto jsonObject = json::object();
 
+    jsonObject["version"] = 2;
+
     jsonObject["narHash"] = narHash.to_string(hashFormat, true);
     jsonObject["narSize"] = narSize;
 
@@ -165,7 +167,7 @@ UnkeyedValidPathInfo::toJSON(const StoreDirConfig & store, bool includeImpureInf
             jsonRefs.emplace_back(store.printStorePath(ref));
     }
 
-    jsonObject["ca"] = ca ? (std::optional{renderContentAddress(*ca)}) : std::nullopt;
+    jsonObject["ca"] = ca;
 
     if (includeImpureInfo) {
         jsonObject["deriver"] = deriver ? (std::optional{store.printStorePath(*deriver)}) : std::nullopt;
@@ -189,6 +191,16 @@ UnkeyedValidPathInfo UnkeyedValidPathInfo::fromJSON(const StoreDirConfig & store
     };
 
     auto & json = getObject(_json);
+
+    // Check version (optional for backward compatibility)
+    nlohmann::json::number_unsigned_t version = 1;
+    if (json.contains("version")) {
+        version = getUnsigned(valueAt(json, "version"));
+        if (version != 1 && version != 2) {
+            throw Error("Unsupported path info JSON format version %d, expected 1 through 2", version);
+        }
+    }
+
     res.narHash = Hash::parseAny(getString(valueAt(json, "narHash")), std::nullopt);
     res.narSize = getUnsigned(valueAt(json, "narSize"));
 
@@ -205,7 +217,15 @@ UnkeyedValidPathInfo UnkeyedValidPathInfo::fromJSON(const StoreDirConfig & store
     // missing is for back-compat.
     if (auto * rawCa0 = optionalValueAt(json, "ca"))
         if (auto * rawCa = getNullable(*rawCa0))
-            res.ca = ContentAddress::parse(getString(*rawCa));
+            switch (version) {
+            case 1:
+                // old string format also used in SQLite DB and .narinfo
+                res.ca = ContentAddress::parse(getString(*rawCa));
+                break;
+            case 2 ... std::numeric_limits<decltype(version)>::max():
+                res.ca = *rawCa;
+                break;
+            }
 
     if (auto * rawDeriver0 = optionalValueAt(json, "deriver"))
         if (auto * rawDeriver = getNullable(*rawDeriver0))
diff --git a/tests/functional/dyn-drv/non-trivial.nix b/tests/functional/dyn-drv/non-trivial.nix
index 3c24ac2ee..87f2d9cfe 100644
--- a/tests/functional/dyn-drv/non-trivial.nix
+++ b/tests/functional/dyn-drv/non-trivial.nix
@@ -51,10 +51,12 @@ builtins.outputOf
             "$word": "hello, from $word!",
             "PATH": ${builtins.toJSON path}
           },
-          "inputDrvs": {
-            $inputDrvs
+          "inputs": {
+            "drvs": {
+              $inputDrvs
+            },
+            "srcs": []
           },
-          "inputSrcs": [],
           "name": "build-$word",
           "outputs": {
             "out": {
@@ -63,7 +65,7 @@ builtins.outputOf
             }
           },
           "system": "${system}",
-          "version": 3
+          "version": 4
         }
       EOF
         drvPath=$(echo "$json" | nix derivation add)
diff --git a/tests/functional/fixed.sh b/tests/functional/fixed.sh
index edf6f88d4..7861392ec 100755
--- a/tests/functional/fixed.sh
+++ b/tests/functional/fixed.sh
@@ -14,7 +14,16 @@ nix-build fixed.nix -A bad --no-out-link && fail "should fail"
 # Building with the bad hash should produce the "good" output path as
 # a side-effect.
 [[ -e $path ]]
-nix path-info --json "$path" | grep fixed:md5:2qk15sxzzjlnpjk9brn7j8ppcd
+nix path-info --json "$path" | jq -e \
+    --arg hash "$(nix hash convert --to base64 "md5:8ddd8be4b179a529afa5f2ffae4b9858")" \
+    '.[].ca == {
+        method: "flat",
+        hash: {
+            algorithm: "md5",
+            format: "base64",
+            hash: $hash
+        },
+    }'
 
 echo 'testing good...'
 nix-build fixed.nix -A good --no-out-link
diff --git a/tests/functional/git-hashing/simple-common.sh b/tests/functional/git-hashing/simple-common.sh
index 08b5c0e71..eaa0a9529 100644
--- a/tests/functional/git-hashing/simple-common.sh
+++ b/tests/functional/git-hashing/simple-common.sh
@@ -47,9 +47,17 @@ try2 () {
     hashFromGit=$(git -C "$repo" rev-parse "HEAD:$hashPath")
     [[ "$hashFromGit" == "$expected" ]]
 
-    local caFromNix
-    caFromNix=$(nix path-info --json "$path" | jq -r ".[] | .ca")
-    [[ "fixed:git:$hashAlgo:$(nix hash convert --to nix32 "$hashAlgo:$hashFromGit")" = "$caFromNix" ]]
+    nix path-info --json "$path" | jq -e \
+        --arg algo "$hashAlgo" \
+        --arg hash "$(nix hash convert --to base64 "$hashAlgo:$hashFromGit")" \
+        '.[].ca == {
+            method: "git",
+            hash: {
+                algorithm: $algo,
+                format: "base64",
+                hash: $hash
+            },
+        }'
 }
 
 test0 () {
diff --git a/tests/functional/impure-derivations.sh b/tests/functional/impure-derivations.sh
index e0b7c3eea..211abccb0 100755
--- a/tests/functional/impure-derivations.sh
+++ b/tests/functional/impure-derivations.sh
@@ -30,7 +30,7 @@ path1_stuff=$(echo "$json" | jq -r .[].outputs.stuff)
 [[ $(< "$path1"/n) = 0 ]]
 [[ $(< "$path1_stuff"/bla) = 0 ]]
 
-[[ $(nix path-info --json "$path1" | jq .[].ca) =~ fixed:r:sha256: ]]
+nix path-info --json "$path1" | jq -e '.[].ca | .method == "nar" and .hash.algorithm == "sha256"'
 
 path2=$(nix build -L --no-link --json --file ./impure-derivations.nix impure | jq -r .[].outputs.out)
 [[ $(< "$path2"/n) = 1 ]]
diff --git a/tests/functional/nix-profile.sh b/tests/functional/nix-profile.sh
index 922162d4b..494b24ddb 100755
--- a/tests/functional/nix-profile.sh
+++ b/tests/functional/nix-profile.sh
@@ -166,7 +166,7 @@ printf 4.0 > "$flake1Dir"/version
 printf Utrecht > "$flake1Dir"/who
 nix profile add "$flake1Dir"
 [[ $("$TEST_HOME"/.nix-profile/bin/hello) = "Hello Utrecht" ]]
-[[ $(nix path-info --json "$(realpath "$TEST_HOME"/.nix-profile/bin/hello)" | jq -r .[].ca) =~ fixed:r:sha256: ]]
+nix path-info --json "$(realpath "$TEST_HOME"/.nix-profile/bin/hello)" | jq -e '.[].ca | .method == "nar" and .hash.algorithm == "sha256"'
 
 # Override the outputs.
 nix profile remove simple flake1
diff --git a/tests/functional/signing.sh b/tests/functional/signing.sh
index 2893efec7..1bcaf2f53 100755
--- a/tests/functional/signing.sh
+++ b/tests/functional/signing.sh
@@ -58,7 +58,7 @@ nix store verify -r "$outPath2" --sigs-needed 1 --trusted-public-keys "$pk1"
 # Build something content-addressed.
 outPathCA=$(IMPURE_VAR1=foo IMPURE_VAR2=bar nix-build ./fixed.nix -A good.0 --no-out-link)
 
-nix path-info --json "$outPathCA" | jq -e '.[] | .ca | startswith("fixed:md5:")'
+nix path-info --json "$outPathCA" | jq -e '.[].ca | .method == "flat" and .hash.algorithm == "md5"'
 
 # Content-addressed paths don't need signatures, so they verify
 # regardless of --sigs-needed.