diff --git a/flake.nix b/flake.nix
index d10b452..d08653f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,10 +2,11 @@
   description = "NixOS configurations for zima, cryochamber, and liminal";
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
+    nixpkgs-23-11.url = "github:NixOS/nixpkgs/nixos-23.11";
+    nixpkgs-25-05.url = "github:NixOS/nixpkgs/nixos-25.05";
+    nixpkgs-25-11.url = "github:NixOS/nixpkgs/nixos-25.11";
     nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixos-unstable";
     sops-nix.url = "github:Mic92/sops-nix";
-    sops-nix.inputs.nixpkgs.follows = "nixpkgs";
     nixos-hardware.url = "github:NixOS/nixos-hardware";
     impermanence.url = "github:nix-community/impermanence";
     talon-nix.url = "github:nix-community/talon-nix";
@@ -13,7 +14,7 @@
     beads-flake.url = "github:steveyegge/beads";
   };
 
-  outputs = { self, nixpkgs, nixpkgs-unstable, sops-nix, nixos-hardware, impermanence, talon-nix, plover-flake, beads-flake, ... }:
+  outputs = { self, nixpkgs-23-11, nixpkgs-25-05, nixpkgs-25-11, nixpkgs-unstable, sops-nix, nixos-hardware, impermanence, talon-nix, plover-flake, beads-flake, ... }:
     let
       system = "x86_64-linux";
       overlay-unstable = final: prev: {
@@ -24,7 +25,7 @@
       };
     in
     {
-      nixosConfigurations.zima = nixpkgs.lib.nixosSystem {
+      nixosConfigurations.zima = nixpkgs-23-11.lib.nixosSystem {
         inherit system;
         specialArgs = {
           inherit impermanence;
@@ -35,7 +36,7 @@
         ];
       };
 
-      nixosConfigurations.cryochamber = nixpkgs.lib.nixosSystem {
+      nixosConfigurations.cryochamber = nixpkgs-25-05.lib.nixosSystem {
         inherit system;
         specialArgs = {
           inherit impermanence;
@@ -46,7 +47,7 @@
         ];
       };
 
-      nixosConfigurations.liminal = nixpkgs.lib.nixosSystem {
+      nixosConfigurations.liminal = nixpkgs-25-11.lib.nixosSystem {
         inherit system;
         specialArgs = {
           inherit nixos-hardware impermanence talon-nix plover-flake beads-flake;