diff --git a/CHANGELOG.md b/CHANGELOG.md
index 994d2e4624..6e7aef780d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 6.3.0-alpha-002 - 2023-11-07
+
+### Changed
+* Update FCS to 'Bugfix for underscore dot lambda: Forbidding expressions not based on the implied _ arg', commit f42bdae84727fc251a6e570c2f1c47a3deffe215
+
+### Added
+* Add support for `while!`. [#2977](https://github.com/fsprojects/fantomas/pull/2977)
+
 ## 6.3.0-alpha-001 - 2023-11-03
 
 ### Changed
diff --git a/Directory.Build.props b/Directory.Build.props
index b065a3b36c..6ff2f04c31 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -40,7 +40,7 @@ Some common use cases include:
     
     <!-- Versions -->
     <PropertyGroup>
-        <FCSCommitHash>97a5b6584b54707e3e8541fe758e1aa22132a8fe</FCSCommitHash>
+        <FCSCommitHash>f42bdae84727fc251a6e570c2f1c47a3deffe215</FCSCommitHash>
         <StreamJsonRpcVersion>2.8.28</StreamJsonRpcVersion>
         <FSharpCoreVersion>6.0.1</FSharpCoreVersion>
     </PropertyGroup>
diff --git a/build.fsx b/build.fsx
index 6bc04fc513..7b08706dd3 100644
--- a/build.fsx
+++ b/build.fsx
@@ -257,6 +257,8 @@ pipeline "Init" {
                "src/Compiler/Utilities/TaggedCollections.fs"
                "src/Compiler/Utilities/illib.fsi"
                "src/Compiler/Utilities/illib.fs"
+               "src/Compiler/Utilities/Cancellable.fsi"
+               "src/Compiler/Utilities/Cancellable.fs"
                "src/Compiler/Utilities/FileSystem.fsi"
                "src/Compiler/Utilities/FileSystem.fs"
                "src/Compiler/Utilities/ildiag.fsi"
diff --git a/src/Fantomas.Core.Tests/ControlStructureTests.fs b/src/Fantomas.Core.Tests/ControlStructureTests.fs
index 56f4de4d36..4a0ea91d7c 100644
--- a/src/Fantomas.Core.Tests/ControlStructureTests.fs
+++ b/src/Fantomas.Core.Tests/ControlStructureTests.fs
@@ -116,6 +116,38 @@ let lookForValue value maxValue =
 lookForValue 10 20
 """
 
+[<Test>]
+let ``while bang`` () =
+    formatSourceString
+        false
+        """
+let goThroughFsharpTicketsAsync() = task {
+    let mutable ticketNumber = 1
+
+    while! doesTicketExistAsync ticketNumber do
+        printfn $"Found a PR or issue #{ticketNumber}."
+        ticketNumber <- ticketNumber + 1
+
+    printfn $"#{ticketNumber} is not created yet."
+}
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let goThroughFsharpTicketsAsync () =
+    task {
+        let mutable ticketNumber = 1
+
+        while! doesTicketExistAsync ticketNumber do
+            printfn $"Found a PR or issue #{ticketNumber}."
+            ticketNumber <- ticketNumber + 1
+
+        printfn $"#{ticketNumber} is not created yet."
+    }
+"""
+
 [<Test>]
 let ``try/with block`` () =
     formatSourceString
diff --git a/src/Fantomas.Core/ASTTransformer.fs b/src/Fantomas.Core/ASTTransformer.fs
index e4eb6cdd40..7082cb47b4 100644
--- a/src/Fantomas.Core/ASTTransformer.fs
+++ b/src/Fantomas.Core/ASTTransformer.fs
@@ -1061,6 +1061,9 @@ let mkExpr (creationAide: CreationAide) (e: SynExpr) : Expr =
     | SynExpr.While(_, ew, ed, StartRange 5 (mWhile, _)) ->
         ExprWhileNode(stn "while" mWhile, mkExpr creationAide ew, mkExpr creationAide ed, exprRange)
         |> Expr.While
+    | SynExpr.WhileBang(_, ew, ed, StartRange 6 (mWhileBang, _)) ->
+        ExprWhileNode(stn "while!" mWhileBang, mkExpr creationAide ew, mkExpr creationAide ed, exprRange)
+        |> Expr.While
     | SynExpr.For(_, _, ident, Some equalsRange, e1, isUp, e2, e3, StartRange 3 (mFor, _)) ->
         ExprForNode(
             stn "for" mFor,
@@ -1726,7 +1729,8 @@ let mkPat (creationAide: CreationAide) (p: SynPat) =
                     | None -> unionRanges ident.idRange pat.Range
                     | Some prefix -> unionRanges prefix.Range pat.Range
 
-                PatRecordField(prefix, mkIdent ident, stn "=" eq, mkPat creationAide pat, range))
+                let eqNode = stn "=" (Option.defaultValue Range.Zero eq)
+                PatRecordField(prefix, mkIdent ident, eqNode, mkPat creationAide pat, range))
 
         PatRecordNode(stn "{" o, fields, stn "}" c, patternRange) |> Pattern.Record
     | SynPat.Const(c, r) -> mkConstant creationAide c r |> Pattern.Const
diff --git a/src/Fantomas.FCS/Fantomas.FCS.fsproj b/src/Fantomas.FCS/Fantomas.FCS.fsproj
index ce91e86056..fa59b89ff5 100644
--- a/src/Fantomas.FCS/Fantomas.FCS.fsproj
+++ b/src/Fantomas.FCS/Fantomas.FCS.fsproj
@@ -64,6 +64,12 @@
     <Compile Include="..\..\.deps\$(FCSCommitHash)\src\Compiler\Utilities\illib.fs">
       <Link>Utilities\illib.fs</Link>
     </Compile>
+    <Compile Include="..\..\.deps\$(FCSCommitHash)\src\Compiler\Utilities\Cancellable.fsi">
+      <Link>Utilities\Cancellable.fsi</Link>
+    </Compile>
+    <Compile Include="..\..\.deps\$(FCSCommitHash)\src\Compiler\Utilities\Cancellable.fs">
+      <Link>Utilities\Cancellable.fs</Link>
+    </Compile>
     <Compile Include="..\..\.deps\$(FCSCommitHash)\src\Compiler\Utilities\FileSystem.fsi">
       <Link>Utilities\FileSystem.fsi</Link>
     </Compile>
diff --git a/src/Fantomas.FCS/Parse.fs b/src/Fantomas.FCS/Parse.fs
index 221faec1bc..892f6640c6 100644
--- a/src/Fantomas.FCS/Parse.fs
+++ b/src/Fantomas.FCS/Parse.fs
@@ -745,6 +745,7 @@ let getSyntaxErrorMessage ctxt =
         | Parser.TOKEN_INLINE -> getErrorString "Parser.TOKEN.INLINE"
         | Parser.TOKEN_WHEN -> getErrorString "Parser.TOKEN.WHEN"
         | Parser.TOKEN_WHILE -> getErrorString "Parser.TOKEN.WHILE"
+        | Parser.TOKEN_WHILE_BANG -> getErrorString "Parser.TOKEN.WHILE.BANG"
         | Parser.TOKEN_WITH -> getErrorString "Parser.TOKEN.WITH"
         | Parser.TOKEN_IF -> getErrorString "Parser.TOKEN.IF"
         | Parser.TOKEN_DO -> getErrorString "Parser.TOKEN.DO"