diff --git a/beacon_chain/rpc/rest_nimbus_api.nim b/beacon_chain/rpc/rest_nimbus_api.nim
index 592dc480d..856f59224 100644
--- a/beacon_chain/rpc/rest_nimbus_api.nim
+++ b/beacon_chain/rpc/rest_nimbus_api.nim
@@ -169,7 +169,8 @@ proc installNimbusApiHandlers*(router: var RestRouter, node: BeaconNode) =
     if contentBody.isNone:
       return RestApiResponse.jsonError(Http400, EmptyRequestBodyError)
 
-    template setGraffitiAux(node: BeaconNode, graffitiStr: string): RestApiResponse =
+    template setGraffitiAux(node: BeaconNode,
+                            graffitiStr: string): RestApiResponse =
       node.graffitiBytes = try:
         GraffitiBytes.init(graffitiStr)
       except CatchableError as err:
@@ -177,21 +178,21 @@ proc installNimbusApiHandlers*(router: var RestRouter, node: BeaconNode) =
                                          err.msg)
       RestApiResponse.jsonResponse((result: true))
 
-    case contentBody.get.contentType
-    of "application/json":
-      let graffitiBytes = decodeBody(GraffitiBytes, contentBody.get)
-      if graffitiBytes.isErr:
+    let body = contentBody.get()
+    if body.contentType == ApplicationJsonMediaType:
+      let graffitiBytes = decodeBody(GraffitiBytes, body)
+      if graffitiBytes.isErr():
         return RestApiResponse.jsonError(Http400, InvalidGraffitiBytesValue,
-                                         $graffitiBytes.error)
-      node.graffitiBytes = graffitiBytes.get
+                                         $graffitiBytes.error())
+      node.graffitiBytes = graffitiBytes.get()
       return RestApiResponse.jsonResponse((result: true))
-    of "text/plain":
-      return node.setGraffitiAux contentBody.get.strData
-    of "application/x-www-form-urlencoded":
-      return node.setGraffitiAux decodeUrl(contentBody.get.strData)
+    elif body.contentType == TextPlainMediaType:
+      return node.setGraffitiAux body.strData()
+    elif body.contentType == UrlEncodedMediaType:
+      return node.setGraffitiAux decodeUrl(body.strData())
     else:
       return RestApiResponse.jsonError(Http400, "Unsupported content type: " &
-                                                $contentBody.get.contentType)
+                                                $body.contentType)
 
   router.api(MethodGet, "/nimbus/v1/graffiti") do (
     ) -> RestApiResponse:
diff --git a/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim b/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim
index 61c763d82..b01269804 100644
--- a/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim
+++ b/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim
@@ -68,6 +68,10 @@ const
   AltairVersion =
     [byte('a'), byte('l'), byte('t'), byte('a'), byte('i'), byte('r')]
 
+  ApplicationJsonMediaType* = MediaType.init("application/json")
+  TextPlainMediaType* = MediaType.init("text/plain")
+  UrlEncodedMediaType* = MediaType.init("application/x-www-form-urlencoded")
+
 type
   EmptyBody* = object
 
@@ -2317,7 +2321,7 @@ proc parseRoot(value: string): Result[Eth2Digest, cstring] =
 
 proc decodeBody*[T](t: typedesc[T],
                     body: ContentBody): Result[T, cstring] =
-  if body.contentType != "application/json":
+  if body.contentType != ApplicationJsonMediaType:
     return err("Unsupported content type")
   let data =
     try:
diff --git a/vendor/nim-chronos b/vendor/nim-chronos
index 2a19e4ca4..939195626 160000
--- a/vendor/nim-chronos
+++ b/vendor/nim-chronos
@@ -1 +1 @@
-Subproject commit 2a19e4ca4c938457205a71adc2cb77f5830c58eb
+Subproject commit 939195626f371048622936e50bf1b1c18979653d
diff --git a/vendor/nim-http-utils b/vendor/nim-http-utils
index 40048e8b3..e88e231df 160000
--- a/vendor/nim-http-utils
+++ b/vendor/nim-http-utils
@@ -1 +1 @@
-Subproject commit 40048e8b3e69284bdb5d4daa0a16ad93402c55db
+Subproject commit e88e231dfcef4585fe3b2fbd9b664dbd28a88040
diff --git a/vendor/nim-presto b/vendor/nim-presto
index ec92aab10..b3dc03be6 160000
--- a/vendor/nim-presto
+++ b/vendor/nim-presto
@@ -1 +1 @@
-Subproject commit ec92aab10259ff2e7bd29d682b1b68c901219bb9
+Subproject commit b3dc03be6e39c5cf2eb52a7778828a36c39fc27c