diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,10 @@
+# 2.1.0
+
+* Relax upper version bounds for `aeson` to `(>= 1.3 && < 1.6)`
+* Relax upper version bounds for `base` to `(>= 4.11 && < 5.0)`
+* Relax upper version bounds for `servant` to `(>= 0.14 && < 0.19)`
+* Relax upper version bounds for `servant-server` to `(>= 0.14 && < 0.19)`
+
 # 2.0.0
 
 The previous version was hopelessly broken.  This completely replaces it.
diff --git a/servant-jsonrpc-server.cabal b/servant-jsonrpc-server.cabal
--- a/servant-jsonrpc-server.cabal
+++ b/servant-jsonrpc-server.cabal
@@ -1,7 +1,7 @@
 cabal-version:       2.4
 
 name:                servant-jsonrpc-server
-version:             2.0.0
+version:             2.1.0
 author:              Ian Shipman <ics@gambolingpangolin.com>
 maintainer:          Ian Shipman <ics@gambolingpangolin.com>
 
@@ -30,10 +30,10 @@
     Servant.Server.JsonRpc
 
   build-depends:
-      aeson                 >= 1.3          && < 1.5
-    , base                  >= 4.11         && < 4.13
+      aeson                 >= 1.3          && < 1.6
+    , base                  >= 4.11         && < 5.0
     , containers            >= 0.5          && < 0.7
     , mtl                   >= 2.2          && < 2.3
-    , servant               >= 0.14         && < 0.17
-    , servant-jsonrpc       >= 1.0.1        && < 1.1
-    , servant-server        >= 0.14         && < 0.17
+    , servant               >= 0.14         && < 0.19
+    , servant-jsonrpc       >= 1.0.1        && < 1.2
+    , servant-server        >= 0.14         && < 0.19
diff --git a/src/Servant/Server/JsonRpc.hs b/src/Servant/Server/JsonRpc.hs
--- a/src/Servant/Server/JsonRpc.hs
+++ b/src/Servant/Server/JsonRpc.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP                   #-}
 {-# LANGUAGE DataKinds             #-}
 {-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE FlexibleInstances     #-}
@@ -9,6 +10,10 @@
 {-# LANGUAGE TypeFamilies          #-}
 {-# LANGUAGE TypeOperators         #-}
 
+#if MIN_VERSION_servant_server(0,18,0)
+{-# LANGUAGE UndecidableInstances  #-}
+#endif
+
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 -- |
@@ -45,7 +50,12 @@
 import           Servant.API              ((:<|>) (..), (:>), JSON,
                                            NoContent (..), Post, ReqBody)
 import           Servant.API.ContentTypes (AllCTRender (..))
+
+#if MIN_VERSION_servant_server(0,18,0)
+import           Servant.Server           (Handler, HasServer (..), HasContextEntry, type (.++), DefaultErrorFormatters, ErrorFormatters)
+#elif MIN_VERSION_servant_server(0,14,0)
 import           Servant.Server           (Handler, HasServer (..))
+#endif
 
 import           Servant.JsonRpc
 
@@ -69,7 +79,11 @@
    :> Post '[JSON] PossibleJsonRpcResponse
 
 
+#if MIN_VERSION_servant_server(0,18,0)
+instance (RouteJsonRpc api, HasContextEntry (context .++ DefaultErrorFormatters) ErrorFormatters) => HasServer (RawJsonRpc api) context where
+#elif MIN_VERSION_servant_server(0,14,0)
 instance RouteJsonRpc api => HasServer (RawJsonRpc api) context where
+#endif
     type ServerT (RawJsonRpc api) m = RpcHandler api m
     route _ cx = route endpoint cx . fmap (serveJsonRpc pxa pxh)
         where