diff --git a/configs/default.nix b/configs/default.nix
index 7aacada..4574e46 100644
--- a/configs/default.nix
+++ b/configs/default.nix
@@ -30,6 +30,7 @@ in {
             tocharian-font = pkgs.callPackage <niveum/packages/tocharian-font.nix> {};
             iolanguage = pkgs.callPackage <niveum/packages/iolanguage.nix> {};
             ix = pkgs.callPackage <niveum/packages/ix.nix> {};
+            unstable = import <nixpkgs-unstable> {inherit (config.nixpkgs) config;};
           };
         };
         overlays = [
diff --git a/configs/fonts.nix b/configs/fonts.nix
index ead4350..1025e5f 100644
--- a/configs/fonts.nix
+++ b/configs/fonts.nix
@@ -1,6 +1,4 @@
-{pkgs, ...}: let
-  nixpkgs-unstable = import <nixpkgs-unstable> {};
-in {
+{pkgs, ...}: {
   nixpkgs.config.joypixels.acceptLicense = true;
   fonts = {
     enableDefaultFonts = true;
@@ -9,17 +7,17 @@ in {
       alegreya
       alegreya-sans
       amiri
-      nixpkgs-unstable.annapurna-sil
+      unstable.annapurna-sil
       cantarell-fonts
       charis-sil
       corefonts
       crimson
       eb-garamond
       etBook
-      nixpkgs-unstable.ezra-sil
+      unstable.ezra-sil
       fira
       font-awesome-ttf
-      nixpkgs-unstable.galatia-sil
+      unstable.galatia-sil
       gentium
       gfs-fonts
       gyre-fonts
diff --git a/configs/packages.nix b/configs/packages.nix
index 945bd62..3f741f2 100644
--- a/configs/packages.nix
+++ b/configs/packages.nix
@@ -8,8 +8,6 @@
   menstruation = pkgs.callPackage <menstruation-backend> {};
   pandoc-doc = pkgs.callPackage <niveum/packages/man/pandoc.nix> {};
 
-  nixpkgs-unstable = import <nixpkgs-unstable> {config.allowUnfree = true;};
-
   zoteroStyle = {
     name,
     sha256,
@@ -35,7 +33,7 @@
     })
   ];
 
-  astrolog = nixpkgs-unstable.astrolog.overrideAttrs (old:
+  astrolog = pkgs.unstable.astrolog.overrideAttrs (old:
     old
     // {
       installPhase = ''
@@ -124,10 +122,10 @@ in {
     electrum
     inkscape
     astrolog
-    nixpkgs-unstable.anki # flashcards
+    unstable.anki # flashcards
     jbofihe # lojbanic software
-    nixpkgs-unstable.zoom-us # video conferencing
-    nixpkgs-unstable.alejandra # nix formatter
+    unstable.zoom-us # video conferencing
+    unstable.alejandra # nix formatter
     pdfgrep # search in pdf
     pdftk # pdf toolkit
     mupdf
diff --git a/configs/telegram-bots/astrology.nix b/configs/telegram-bots/astrology.nix
index 6f24595..c2a537f 100644
--- a/configs/telegram-bots/astrology.nix
+++ b/configs/telegram-bots/astrology.nix
@@ -3,7 +3,6 @@
   lib,
   ...
 }: let
-  nixpkgs-unstable = import <nixpkgs-unstable> {};
   toSymbols = pkgs.writers.writeDash "to-symbols" ''
     ${pkgs.gnused}/bin/sed '
       s/\bTri\b/△/;
@@ -50,8 +49,8 @@ in {
       now=$(${pkgs.coreutils}/bin/date +%_H:%M | ${pkgs.gnused}/bin/sed 's/^\s*//')
       date=$(${pkgs.coreutils}/bin/date +'%m %d %Y')
       {
-        ${nixpkgs-unstable.astrolog}/bin/astrolog -qd $date -zN Berlin -Yt -Yd -d -R Uranus Neptune Pluto "North Node"
-        ${nixpkgs-unstable.astrolog}/bin/astrolog -Yt -Yd -q 10 22 1999 6:32 -zN Kassel -td $date -R Uranus Neptune Pluto "North Node"
+        ${pkgs.unstable.astrolog}/bin/astrolog -qd $date -zN Berlin -Yt -Yd -d -R Uranus Neptune Pluto "North Node"
+        ${pkgs.unstable.astrolog}/bin/astrolog -Yt -Yd -q 10 22 1999 6:32 -zN Kassel -td $date -R Uranus Neptune Pluto "North Node"
       } | ${toSymbols} | ${pkgs.coreutils}/bin/sort -n | ${pkgs.gnugrep}/bin/grep "^$now" || :
     '');
   };
diff --git a/systems/makanek/configuration.nix b/systems/makanek/configuration.nix
index b404838..248d6ef 100644
--- a/systems/makanek/configuration.nix
+++ b/systems/makanek/configuration.nix
@@ -62,6 +62,10 @@ in {
     useDHCP = false;
   };
 
+  nixpkgs.config.packageOverrides = pkgs: {
+    unstable = import <nixpkgs-unstable> {inherit (config.nixpkgs) config;};
+  };
+
   system.stateVersion = "20.03";
 
   services.nginx = {
diff --git a/systems/makanek/hedgedoc.nix b/systems/makanek/hedgedoc.nix
index b893f0d..cfeb703 100644
--- a/systems/makanek/hedgedoc.nix
+++ b/systems/makanek/hedgedoc.nix
@@ -5,7 +5,6 @@
 }: let
   backupLocation = "/var/lib/codimd-backup";
   stateLocation = "/var/lib/codimd/state.sqlite";
-  nixpkgs-unstable = import <nixpkgs-unstable> {};
   domain = "pad.kmein.de";
   inherit (import <niveum/lib>) tmpfilesConfig;
 in {
@@ -61,7 +60,7 @@ in {
   systemd.services.hedgedoc-backup = {
     description = "Hedgedoc backup service";
     script = ''
-      ${nixpkgs-unstable.sqlite}/bin/sqlite3 -json ${stateLocation} "select shortid, alias, ownerId, content from Notes" \
+      ${pkgs.unstable.sqlite}/bin/sqlite3 -json ${stateLocation} "select shortid, alias, ownerId, content from Notes" \
       | ${
         pkgs.writers.writePython3 "hedgedoc-json-to-fs.py" {} ''
           import json