diff --git a/home.nix b/home.nix
index 11f8371..8139764 100644
--- a/home.nix
+++ b/home.nix
@@ -43,7 +43,16 @@
     ];
 
     activation = {
-      cleanAppCaches = lib.hm.dag.entryAfter [ "onFilesChange" "installPackages" "copyFonts" ] ''
+      updateAppCaches = lib.hm.dag.entryAfter [ "onFilesChange" "installPackages" "copyFonts" ] ''
+        # nixpkgs
+        echo "Calculating new NIX_PATH value ..."
+        mkdir -p "$HOME/.cache/fish"
+        nix flake metadata ~/.config/nixpkgs --json 2>/dev/null | \
+          jq -r '.locks.nodes.nixpkgs.locked | "\(.type):\(.owner)/\(.repo)/\(.rev)"' | \
+          xargs -I {} nix flake metadata {} --json | \
+          jq -r '. | "nixpkgs=\(.path)"' >"$HOME/.cache/fish/nix_path_value"
+
+        # neovim
         echo -n "Running LuaCacheClear: "
         nvim -c 'try | execute "LuaCacheClear" | echo "Done" | catch /.*/ | echo "Command not found" | endtry | q' --headless
         printf '\nRemoving luacache file: '
diff --git a/programs/fish.nix b/programs/fish.nix
index 0654eec..3a43156 100644
--- a/programs/fish.nix
+++ b/programs/fish.nix
@@ -36,7 +36,7 @@
       ytdl = "ytdl_with_options";
       ytdl_mp4 = "ytdl_with_options -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]'";
       yti = "ytdl_with_options -F";
-      upa = "nix-channel --update nixpkgs && nix flake update ~/.config/nixpkgs -v";
+      upa = "nix flake update ~/.config/nixpkgs -v";
       upp = "nix flake update ./ -v";
       upn = "$HOME/.config/nixpkgs/programs/nvim/update-plugins.sh";
       ucl = "nix-collect-garbage -d && nix-store --gc && nix-store --optimise -v";
@@ -54,6 +54,10 @@
     };
 
     shellInit = ''
+      if test -e "$HOME/.cache/fish/nix_path_value"
+        set -gx NIX_PATH (cat "$HOME/.cache/fish/nix_path_value")
+      end
+
       if test -e /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh
         fenv source /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh
       end