diff --git a/nix/uniworx/backend.nix b/nix/uniworx/backend.nix
index 03fdb8431..175111e78 100644
--- a/nix/uniworx/backend.nix
+++ b/nix/uniworx/backend.nix
@@ -26,7 +26,7 @@ in {
         cp -pr --reflink=auto ./. $out
       '';
     };
-    compiler-nix-name = "ghc8104";
+    compiler-nix-name = "ghc94";
     # stack-sha256 = "1n7z294ldv2rjkfj1vs3kqmnbp34m2scrmyrp5kwmga9vp86fd9z"; # produces errors gregor does not understand :(
     modules = [
       {
diff --git a/stack.yaml b/stack.yaml
index 4781e3c0f..2c5a94f9b 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -127,5 +127,5 @@ extra-deps:
   - ldap-client-0.4.2@sha256:2ddd8e7aa2dcbe9444775224e12abf4c42e0133b4d2d6b0d1324c4bd7d4169ca,2225
   - memcached-binary-0.2.0@sha256:3314b765ef10f959862577e55809bc181d16dfd3ff9443b62499b5b393eea6b3,2451
 
-resolver: lts-22.4
+resolver: lts-21.25
 allow-newer: true
diff --git a/stack.yaml.lock b/stack.yaml.lock
index c4b112033..15631aa92 100644
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -520,7 +520,7 @@ packages:
     hackage: memcached-binary-0.2.0@sha256:3314b765ef10f959862577e55809bc181d16dfd3ff9443b62499b5b393eea6b3,2451
 snapshots:
 - completed:
-    sha256: 8b211c5a6aad3787e023dfddaf7de7868968e4f240ecedf14ad1c5b2199046ca
-    size: 714097
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/4.yaml
-  original: lts-22.4
+    sha256: a81fb3877c4f9031e1325eb3935122e608d80715dc16b586eb11ddbff8671ecd
+    size: 640086
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/21/25.yaml
+  original: lts-21.25