diff --git a/src/PostgresWebsockets/Claims.hs b/src/PostgresWebsockets/Claims.hs
index 06204b1..dce6d91 100644
--- a/src/PostgresWebsockets/Claims.hs
+++ b/src/PostgresWebsockets/Claims.hs
@@ -89,8 +89,8 @@ claims2map = val2map . toJSON
 hs256jwk :: ByteString -> JWK
 hs256jwk key =
   fromKeyMaterial km
-    & jwkUse .~ Just Sig
-    & jwkAlg .~ (Just $ JWSAlg HS256)
+    & jwkUse ?~ Sig
+    & jwkAlg ?~ JWSAlg HS256
  where
   km = OctKeyMaterial (OctKeyParameters (JOSE.Types.Base64Octets key))
 
diff --git a/stack.yaml b/stack.yaml
index 886c675..6627d26 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-12.14
+resolver: lts-12.16
 extra-deps: []
 ghc-options:
   postgres-websockets: -O2 -Wall -fwarn-identities -fno-warn-redundant-constraints