diff --git a/backend/shell.nix b/backend/shell.nix
index 7e83bc2..a24dad2 100644
--- a/backend/shell.nix
+++ b/backend/shell.nix
@@ -5,6 +5,8 @@ pkgs.mkShell {
     haskell-language-server
     stack
     stylish-haskell
+
+    libnotify
   ];
 
 }
diff --git a/backend/src/State/RoomsState.hs b/backend/src/State/RoomsState.hs
index af7e40b..f42eff1 100644
--- a/backend/src/State/RoomsState.hs
+++ b/backend/src/State/RoomsState.hs
@@ -62,7 +62,7 @@ roomStateDiffInOpenRooms newData = do
   current <- getRoomDataState
 
   let newRooms = filter roomNotEmpty $ filter (\newRoom -> isNothing $ find (sameName newRoom) current) newData
-  let oldRooms = filter (\newRoom -> isJust $ find (sameName newRoom) current) newData
+  let oldRooms = filter roomNotEmpty $ filter (\oldRoom -> isNothing $ find (sameName oldRoom) newData) current
 
   return (newRooms, oldRooms)
 
diff --git a/backend/stack.yaml b/backend/stack.yaml
index 5383a0f..e142431 100644
--- a/backend/stack.yaml
+++ b/backend/stack.yaml
@@ -14,8 +14,9 @@
 # Use the latest resolver that uses the same ghc version
 # as build for nixos
 # this way we can use prebuild binaries for hls
-#resolver: nightly-2022-11-12
-#resolver: ghc-9.2.4
+# go to
+# https://www.stackage.org/
+# and select the lts that is matching you hls version
 resolver: lts-22.43
 #
 # The location of a snapshot can be provided as a file or url. Stack assumes