diff --git a/lib/attrsets.nix b/lib/attrsets.nix
index 8bb4ef972fd8c..7b8feb4fe89bb 100644
--- a/lib/attrsets.nix
+++ b/lib/attrsets.nix
@@ -5,7 +5,7 @@
 
 let
   inherit (builtins) head length;
-  inherit (lib.trivial) isInOldestRelease mergeAttrs warn warnIf;
+  inherit (lib.trivial) oldestSupportedReleaseIsAtLeast mergeAttrs warn warnIf;
   inherit (lib.strings) concatStringsSep concatMapStringsSep escapeNixIdentifier sanitizeDerivationName;
   inherit (lib.lists) foldr foldl' concatMap elemAt all partition groupBy take foldl;
 in
@@ -2137,6 +2137,6 @@ rec {
     "lib.zip is a deprecated alias of lib.zipAttrsWith." zipAttrsWith;
 
   # DEPRECATED
-  cartesianProductOfSets = warnIf (isInOldestRelease 2405)
+  cartesianProductOfSets = warnIf (oldestSupportedReleaseIsAtLeast 2405)
     "lib.cartesianProductOfSets is a deprecated alias of lib.cartesianProduct." cartesianProduct;
 }
diff --git a/lib/default.nix b/lib/default.nix
index 4d0035945aaa9..aff1df150f13b 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -73,7 +73,7 @@ let
     inherit (self.trivial) id const pipe concat or and xor bitAnd bitOr bitXor
       bitNot boolToString mergeAttrs flip mapNullable inNixShell isFloat min max
       importJSON importTOML warn warnIf warnIfNot throwIf throwIfNot checkListOfEnum
-      info showWarnings nixpkgsVersion version isInOldestRelease
+      info showWarnings nixpkgsVersion version isInOldestRelease oldestSupportedReleaseIsAtLeast
       mod compare splitByAndCompare seq deepSeq lessThan add sub
       functionArgs setFunctionArgs isFunction toFunction mirrorFunctionArgs
       fromHexString toHexString toBaseDigits inPureEvalMode isBool isInt pathExists
diff --git a/lib/modules.nix b/lib/modules.nix
index 3472085a763b3..855ffaf25ed81 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -23,7 +23,7 @@ let
     isAttrs
     isBool
     isFunction
-    isInOldestRelease
+    oldestSupportedReleaseIsAtLeast
     isList
     isString
     length
@@ -1030,7 +1030,7 @@ let
   mkForce = mkOverride 50;
   mkVMOverride = mkOverride 10; # used by ‘nixos-rebuild build-vm’
 
-  defaultPriority = warnIf (isInOldestRelease 2305) "lib.modules.defaultPriority is deprecated, please use lib.modules.defaultOverridePriority instead." defaultOverridePriority;
+  defaultPriority = warnIf (oldestSupportedReleaseIsAtLeast 2305) "lib.modules.defaultPriority is deprecated, please use lib.modules.defaultOverridePriority instead." defaultOverridePriority;
 
   mkFixStrictness = warn "lib.mkFixStrictness has no effect and will be removed. It returns its argument unmodified, so you can just remove any calls." id;
 
@@ -1146,8 +1146,8 @@ let
   }: doRename {
     inherit from to;
     visible = false;
-    warn = isInOldestRelease sinceRelease;
-    use = warnIf (isInOldestRelease sinceRelease)
+    warn = oldestSupportedReleaseIsAtLeast sinceRelease;
+    use = warnIf (oldestSupportedReleaseIsAtLeast sinceRelease)
       "Obsolete option `${showOption from}' is used. It was renamed to `${showOption to}'.";
   };
 
diff --git a/lib/sources.nix b/lib/sources.nix
index f61ea306aec56..62c4a214536bd 100644
--- a/lib/sources.nix
+++ b/lib/sources.nix
@@ -256,15 +256,15 @@ let
 
 in {
 
-  pathType = lib.warnIf (lib.isInOldestRelease 2305)
+  pathType = lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2305)
     "lib.sources.pathType has been moved to lib.filesystem.pathType."
     lib.filesystem.pathType;
 
-  pathIsDirectory = lib.warnIf (lib.isInOldestRelease 2305)
+  pathIsDirectory = lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2305)
     "lib.sources.pathIsDirectory has been moved to lib.filesystem.pathIsDirectory."
     lib.filesystem.pathIsDirectory;
 
-  pathIsRegularFile = lib.warnIf (lib.isInOldestRelease 2305)
+  pathIsRegularFile = lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2305)
     "lib.sources.pathIsRegularFile has been moved to lib.filesystem.pathIsRegularFile."
     lib.filesystem.pathIsRegularFile;
 
diff --git a/lib/strings.nix b/lib/strings.nix
index ffde541c69583..d9a2d786ed289 100644
--- a/lib/strings.nix
+++ b/lib/strings.nix
@@ -2272,7 +2272,7 @@ rec {
     isCoercibleToString :: a -> bool
     ```
   */
-  isCoercibleToString = lib.warnIf (lib.isInOldestRelease 2305)
+  isCoercibleToString = lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2305)
     "lib.strings.isCoercibleToString is deprecated in favor of either isStringLike or isConvertibleWithToString. Only use the latter if it needs to return true for null, numbers, booleans and list of similarly coercibles."
     isConvertibleWithToString;
 
diff --git a/lib/trivial.nix b/lib/trivial.nix
index f0afbf609fcab..205224126094e 100644
--- a/lib/trivial.nix
+++ b/lib/trivial.nix
@@ -397,6 +397,15 @@ in {
     Set it to the upcoming release, matching the nixpkgs/.version file.
   */
   isInOldestRelease =
+    lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2411)
+      "lib.isInOldestRelease is deprecated. Use lib.oldestSupportedReleaseIsAtLeast instead."
+    lib.oldestSupportedReleaseIsAtLeast;
+
+  /**
+    Alias for `isInOldestRelease` introduced in 24.11.
+    Use `isInOldestRelease` in expressions outside of Nixpkgs for greater compatibility.
+   */
+  oldestSupportedReleaseIsAtLeast =
     release:
       release <= lib.trivial.oldestSupportedRelease;
 
diff --git a/nixos/lib/testing/nodes.nix b/nixos/lib/testing/nodes.nix
index 9aecca10ac6b2..8b14d0a3bffdb 100644
--- a/nixos/lib/testing/nodes.nix
+++ b/nixos/lib/testing/nodes.nix
@@ -151,7 +151,7 @@ in
     nodesCompat =
       mapAttrs
         (name: config: config // {
-          config = lib.warnIf (lib.isInOldestRelease 2211)
+          config = lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2211)
             "Module argument `nodes.${name}.config` is deprecated. Use `nodes.${name}` instead."
             config;
         })
diff --git a/pkgs/build-support/substitute/substitute.nix b/pkgs/build-support/substitute/substitute.nix
index 37233a306840d..e6f0835c8f8e6 100644
--- a/pkgs/build-support/substitute/substitute.nix
+++ b/pkgs/build-support/substitute/substitute.nix
@@ -39,7 +39,7 @@ let
   optionalDeprecationWarning =
     # substitutions is only available starting 24.05.
     # TODO: Remove support for replacements sometime after the next release
-    lib.warnIf (args ? replacements && lib.isInOldestRelease 2405) ''
+    lib.warnIf (args ? replacements && lib.oldestSupportedReleaseIsAtLeast 2405) ''
       pkgs.substitute: For "${name}", `replacements` is used, which is deprecated since it doesn't support arguments with spaces. Use `substitutions` instead:
         substitutions = [ ${deprecationReplacement} ];'';
 in
diff --git a/pkgs/development/haskell-modules/lib/compose.nix b/pkgs/development/haskell-modules/lib/compose.nix
index 3661c74d499a2..cbefc44bb01d0 100644
--- a/pkgs/development/haskell-modules/lib/compose.nix
+++ b/pkgs/development/haskell-modules/lib/compose.nix
@@ -466,7 +466,7 @@ rec {
     which is cross aware instead.
   */
   generateOptparseApplicativeCompletions = commands: pkg:
-    lib.warnIf (lib.isInOldestRelease 2211) "haskellLib.generateOptparseApplicativeCompletions is deprecated in favor of haskellPackages.generateOptparseApplicativeCompletions. Please change ${pkg.name} to use the latter and make sure it uses its matching haskell.packages set!"
+    lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2211) "haskellLib.generateOptparseApplicativeCompletions is deprecated in favor of haskellPackages.generateOptparseApplicativeCompletions. Please change ${pkg.name} to use the latter and make sure it uses its matching haskell.packages set!"
       (pkgs.lib.foldr __generateOptparseApplicativeCompletion pkg commands);
 
   /*
@@ -475,7 +475,7 @@ rec {
     which is cross aware instead.
   */
   generateOptparseApplicativeCompletion = command: pkg:
-    lib.warnIf (lib.isInOldestRelease 2211) "haskellLib.generateOptparseApplicativeCompletion is deprecated in favor of haskellPackages.generateOptparseApplicativeCompletions (plural!). Please change ${pkg.name} to use the latter and make sure it uses its matching haskell.packages set!"
+    lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2211) "haskellLib.generateOptparseApplicativeCompletion is deprecated in favor of haskellPackages.generateOptparseApplicativeCompletions (plural!). Please change ${pkg.name} to use the latter and make sure it uses its matching haskell.packages set!"
       (__generateOptparseApplicativeCompletion command pkg);
 
   # Don't fail at configure time if there are multiple versions of the
diff --git a/pkgs/development/interpreters/python/passthrufun.nix b/pkgs/development/interpreters/python/passthrufun.nix
index b06433113b6b3..dc2f3c7dc17cf 100644
--- a/pkgs/development/interpreters/python/passthrufun.nix
+++ b/pkgs/development/interpreters/python/passthrufun.nix
@@ -93,7 +93,7 @@ in rec {
     inherit hasDistutilsCxxPatch;
     # Remove after 24.11 is released.
     pythonForBuild =
-      lib.warnIf (lib.isInOldestRelease 2311) "`pythonForBuild` (from `python*`) has been renamed to `pythonOnBuildForHost`"
+      lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2311) "`pythonForBuild` (from `python*`) has been renamed to `pythonOnBuildForHost`"
         pythonOnBuildForHost_overridden;
     pythonOnBuildForHost = pythonOnBuildForHost_overridden;