diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# Fixed in 0.1.6.2
+- Removed `undefined` in empty `mset` case
+
 # New in 0.1.6.0
 
 - `getrange`, `setrange`, `getbit`, `setbit` added for new ByteString-based primitive
diff --git a/hlrdb-core.cabal b/hlrdb-core.cabal
--- a/hlrdb-core.cabal
+++ b/hlrdb-core.cabal
@@ -1,5 +1,5 @@
 name:                hlrdb-core
-version:             0.1.6.1
+version:             0.1.6.2
 synopsis:            High-level Redis Database Core API
 description:         A library for type-driven interaction with Redis
 license:             MIT
@@ -31,7 +31,7 @@
   build-depends: base >= 4.9 && < 5.0
                , bytestring >= 0.10.8.2 && < 0.12
                , hashable >= 1.2.6.1 && < 1.4
-               , hedis >= 0.10.1 && < 0.15
+               , hedis >= 0.14 && < 0.15
                , lens >= 4.16 && < 5.1
                , mtl ^>= 2.2.2
                , profunctors >= 5.2.2 && < 5.7
diff --git a/src/HLRDB/Structures/Basic.hs b/src/HLRDB/Structures/Basic.hs
--- a/src/HLRDB/Structures/Basic.hs
+++ b/src/HLRDB/Structures/Basic.hs
@@ -75,7 +75,7 @@
     mdel' [] = pure 0
     mdel' xs = unwrap $ liftRedis $ Redis.del xs
     
-    mset' [] = pure undefined
+    mset' [] = pure Ok
     mset' xs = unwrap $ liftRedis $ Redis.mset xs
 
 -- | Set a value together with a given expiration timeout (in seconds).