diff --git a/modules/home-manager.nix b/modules/home-manager.nix
index 5d0a35a..f4aa7dd 100644
--- a/modules/home-manager.nix
+++ b/modules/home-manager.nix
@@ -7,11 +7,6 @@ with lib;
 let
   cfg = config.home-manager;
 
-  tryEval = builtins.tryEval (home-manager.path + "/modules/modules.nix");
-  assertionNixpkgs = types ? submoduleWith;
-  assertionHomeManager = tryEval.success && builtins.functionArgs (import tryEval.value) ? useNixpkgsModule;
-  assertion = assertionNixpkgs && assertionHomeManager;
-
   extendedLib = import (home-manager.path + "/modules/lib/stdlib-extended.nix") pkgs.lib;
 
   hmModule = types.submoduleWith {
@@ -54,10 +49,7 @@ in
       };
 
       config = mkOption {
-        type =
-          if assertion
-          then types.nullOr hmModule
-          else types.unspecified;
+        type = types.nullOr hmModule;
         default = null;
         description = "Home Manager configuration.";
       };
@@ -81,56 +73,37 @@ in
 
   ###### implementation
 
-  config = mkIf (cfg.config != null) (mkMerge [
+  config = mkIf (cfg.config != null) {
 
-    {
-      assertions = [
-        {
-          assertion = assertionNixpkgs;
-          message = "You are currently using release-19.09 branch or older of nixpkgs, you need "
-            + "to update to the release-20.03 channel or newer.";
-        }
-        {
-          assertion = assertionHomeManager;
-          message = "You are currently using release-19.09 branch or older of home-manager, you need "
-            + "to update to the release-20.03 channel or newer.";
-        }
-      ];
-    }
+    inherit (cfg.config) assertions warnings;
 
-    # hack to determine if cfg.config is a valid home-manager config
-    (mkIf (cfg.config ? home && cfg.config.home ? activationPackage) {
-
-      inherit (cfg.config) assertions warnings;
-
-      build = {
-        activationBefore = mkIf cfg.useUserPackages {
-          setPriorityHomeManagerPath = ''
-            if nix-env -q | grep '^home-manager-path$'; then
-              $DRY_RUN_CMD nix-env $VERBOSE_ARG --set-flag priority 120 home-manager-path
-            fi
-          '';
-        };
-
-        activationAfter.homeManager = concatStringsSep " " (
-          optional
-            (cfg.backupFileExtension != null)
-            "HOME_MANAGER_BACKUP_EXT='${cfg.backupFileExtension}'"
-          ++ [ "${cfg.config.home.activationPackage}/activate" ]
-        );
+    build = {
+      activationBefore = mkIf cfg.useUserPackages {
+        setPriorityHomeManagerPath = ''
+          if nix-env -q | grep '^home-manager-path$'; then
+            $DRY_RUN_CMD nix-env $VERBOSE_ARG --set-flag priority 120 home-manager-path
+          fi
+        '';
       };
 
-      environment.packages = mkIf cfg.useUserPackages cfg.config.home.packages;
+      activationAfter.homeManager = concatStringsSep " " (
+        optional
+          (cfg.backupFileExtension != null)
+          "HOME_MANAGER_BACKUP_EXT='${cfg.backupFileExtension}'"
+        ++ [ "${cfg.config.home.activationPackage}/activate" ]
+      );
+    };
 
-      # home-manager has a quirk redefining the profile location
-      # to "/etc/profiles/per-user/${cfg.username}" if useUserPackages is on.
-      # https://github.com/nix-community/home-manager/blob/0006da1381b87844c944fe8b925ec864ccf19348/modules/home-environment.nix#L414
-      # Fortunately, it's not that hard to us to workaround with just a symlink.
-      environment.etc = mkIf cfg.useUserPackages {
-        "profiles/per-user/${config.user.userName}".source =
-          builtins.toPath "${config.user.home}/.nix-profile";
-      };
-    })
+    environment.packages = mkIf cfg.useUserPackages cfg.config.home.packages;
 
-  ]);
+    # home-manager has a quirk redefining the profile location
+    # to "/etc/profiles/per-user/${cfg.username}" if useUserPackages is on.
+    # https://github.com/nix-community/home-manager/blob/0006da1381b87844c944fe8b925ec864ccf19348/modules/home-environment.nix#L414
+    # Fortunately, it's not that hard to us to workaround with just a symlink.
+    environment.etc = mkIf cfg.useUserPackages {
+      "profiles/per-user/${config.user.userName}".source =
+        builtins.toPath "${config.user.home}/.nix-profile";
+    };
+
+  };
 }