diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Revision history for haskell-lsp
 
+## 0.2.2.0  -- 2018-05-04
+
+* Make Diagnostic relatedInformation optional, as per the LSP Spec. By @Bubba.
+
 ## 0.2.1.0  -- 2018-05-02
 
 * Support GHC 8.4.2
diff --git a/example/Main.hs b/example/Main.hs
--- a/example/Main.hs
+++ b/example/Main.hs
@@ -316,7 +316,7 @@
               Nothing  -- code
               (Just "lsp-hello") -- source
               "Example diagnostic message"
-              (J.List [])
+              (Just (J.List []))
             ]
   -- reactorSend $ J.NotificationMessage "2.0" "textDocument/publishDiagnostics" (Just r)
   publishDiagnostics 100 fileUri mversion (partitionBySource diags)
diff --git a/haskell-lsp.cabal b/haskell-lsp.cabal
--- a/haskell-lsp.cabal
+++ b/haskell-lsp.cabal
@@ -1,5 +1,5 @@
 name:                haskell-lsp
-version:             0.2.1.0
+version:             0.2.2.0
 synopsis:            Haskell library for the Microsoft Language Server Protocol
 
 description:         An implementation of the types, and basic message server to
diff --git a/test/DiagnosticsSpec.hs b/test/DiagnosticsSpec.hs
--- a/test/DiagnosticsSpec.hs
+++ b/test/DiagnosticsSpec.hs
@@ -34,14 +34,14 @@
     rng = J.Range (J.Position 0 1) (J.Position 3 0)
     loc = J.Location (J.Uri "file") rng
   in
-    J.Diagnostic rng Nothing Nothing ms str (J.List [J.DiagnosticRelatedInformation loc str])
+    J.Diagnostic rng Nothing Nothing ms str (Just (J.List [J.DiagnosticRelatedInformation loc str]))
 
 mkDiagnostic2 :: Maybe J.DiagnosticSource -> Text -> J.Diagnostic
 mkDiagnostic2 ms str =
   let
     rng = J.Range (J.Position 4 1) (J.Position 5 0)
     loc = J.Location (J.Uri "file") rng
-  in J.Diagnostic rng Nothing Nothing ms str (J.List [J.DiagnosticRelatedInformation loc str])
+  in J.Diagnostic rng Nothing Nothing ms str (Just (J.List [J.DiagnosticRelatedInformation loc str]))
 
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