diff --git a/shell.nix b/shell.nix
index 931e7ade0..e6178f7b0 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,11 +1,8 @@
-{ nixpkgs ? import <nixpkgs> {}, compiler ? null }:
+{ nixpkgs ? import <nixpkgs>, compiler ? null }:
 
 let
-  inherit (nixpkgs) pkgs;
-
-  haskellPackages = if isNull compiler
-                       then pkgs.haskellPackages
-                       else pkgs.haskell.packages."${compiler}";
+  inherit (nixpkgs {}) pkgs;
+  haskellPackages = if isNull compiler then pkgs.haskellPackages else pkgs.haskell.packages."${compiler}";
 
   drv = haskellPackages.callPackage ./uniworx.nix {};
 
@@ -26,21 +23,29 @@ let
     shellHook = ''
       export PROMPT_INFO="${oldAttrs.name}"
 
-      pgDir=$(mktemp -d)
-      pgSockDir=$(mktemp -d)
-      pgLogFile=$(mktemp)
-      initdb --no-locale -D ''${pgDir}
-      pg_ctl start -D ''${pgDir} -l ''${pgLogFile} -w -o "-k ''${pgSockDir} -c listen_addresses=''' -c hba_file='${postgresHba}' -c unix_socket_permissions=0700"
-      export PGHOST=''${pgSockDir} PGLOG=''${pgLogFile}
-      psql -f ${postgresSchema} postgres
-      printf "Postgres logfile is %s\nPostgres socket directory is %s\n" ''${pgLogFile} ''${pgSockDir}
+      if [[ -z "$PGHOST" ]]; then
+        set -xe
 
-      cleanup() {
-          pg_ctl stop -D ''${pgDir}
-          rm -rvf ''${pgDir} ''${pgSockDir} ''${pgLogFile}
-      }
+        pgDir=$(mktemp -d)
+        pgSockDir=$(mktemp -d)
+        pgLogFile=$(mktemp)
+        initdb --no-locale -D ''${pgDir}
+        pg_ctl start -D ''${pgDir} -l ''${pgLogFile} -w -o "-k ''${pgSockDir} -c listen_addresses=''' -c hba_file='${postgresHba}' -c unix_socket_permissions=0700"
+        export PGHOST=''${pgSockDir} PGLOG=''${pgLogFile}
+        psql -f ${postgresSchema} postgres
+        printf "Postgres logfile is %s\nPostgres socket directory is %s\n" ''${pgLogFile} ''${pgSockDir}
 
-      trap cleanup EXIT
+        cleanup() {
+            set +e -x
+            pg_ctl stop -D ''${pgDir}
+            rm -rvf ''${pgDir} ''${pgSockDir} ''${pgLogFile}
+            set +x
+        }
+
+        trap cleanup EXIT
+
+        set +xe
+      fi
 
       ${oldAttrs.shellHook}
     '';
diff --git a/stack.nix b/stack.nix
index 7a8a0dcbf..e986ba349 100644
--- a/stack.nix
+++ b/stack.nix
@@ -1,8 +1,14 @@
-{ ghc, nixpkgs ? (import <nixpkgs> {}) }:
+{ ghc, nixpkgs ? import <nixpkgs> }:
 
 let
-  inherit (nixpkgs) haskell pkgs;
-  haskellPackages = if ghc.version == pkgs.haskellPackages.ghc.version then pkgs.haskellPackages else pkgs.haskell.packages."ghc${builtins.replaceStrings ["."] [""] ghc.version}";
+  snapshot = "lts-10.5";
+  stackage = import (fetchTarball {
+    url = "https://stackage.serokell.io/drczwlyf6mi0ilh3kgv01wxwjfgvq14b-stackage/default.nix.tar.gz";
+    sha256 = "1bwlbxx6np0jfl6z9gkmmcq22crm0pa07a8zrwhz5gkal64y6jpz";
+  });
+  inherit (nixpkgs { overlays = [ stackage."${snapshot}" ]; }) haskell pkgs;
+
+  haskellPackages = pkgs.haskell.packages."${snapshot}";
 in haskell.lib.buildStackProject {
   inherit ghc;
   name = "stackenv";
diff --git a/stack.yaml b/stack.yaml
index c4f2d4dba..94be126d8 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -17,6 +17,10 @@ packages:
       git: https://github.com/pngwjpgh/encoding.git
       commit: 67bb87ceff53f0178c988dd4e15eeb2daee92b84
     extra-dep: true
+  - location:
+      git: https://github.com/pngwjpgh/memcached-binary.git
+      commit: b5461747e7be226d3b67daebc3c9aefe8a4490ad
+    extra-dep: true
 
 extra-deps:
   - colonnade-1.2.0
@@ -45,8 +49,4 @@ extra-deps:
   - quickcheck-classes-0.4.14
   - semirings-0.2.1.1
 
-  - memcached-binary-0.2.0
-
-allow-newer: true
-
 resolver: lts-10.5