diff --git a/Sources/SwiftParser/Availability.swift b/Sources/SwiftParser/Availability.swift
index a6d6be4ebe1..c329bfc2fd4 100644
--- a/Sources/SwiftParser/Availability.swift
+++ b/Sources/SwiftParser/Availability.swift
@@ -218,6 +218,13 @@ extension Parser {
       (unexpectedBeforePlatform, platform) = self.expect(.identifier)
     }
 
+    let unexpectedComparison: RawUnexpectedNodesSyntax?
+    if let greaterThanOrEqualTo = self.consumeIfContextualPunctuator(">=") {
+      unexpectedComparison = RawUnexpectedNodesSyntax([greaterThanOrEqualTo], arena: self.arena)
+    } else {
+      unexpectedComparison = nil
+    }
+
     let version: RawVersionTupleSyntax?
     if self.at(.integerLiteral, .floatingLiteral) {
       version = self.parseVersionTuple()
@@ -228,6 +235,7 @@ extension Parser {
     return RawAvailabilityVersionRestrictionSyntax(
       unexpectedBeforePlatform,
       platform: platform,
+      unexpectedComparison,
       version: version,
       arena: self.arena
     )
diff --git a/Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift b/Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift
index 21f0e7ef28b..51b2fe1a966 100644
--- a/Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift
+++ b/Sources/SwiftParserDiagnostics/ParseDiagnosticsGenerator.swift
@@ -440,6 +440,25 @@ public class ParseDiagnosticsGenerator: SyntaxAnyVisitor {
     return .visitChildren
   }
 
+  public override func visit(_ node: AvailabilityVersionRestrictionSyntax) -> SyntaxVisitorContinueKind {
+    if shouldSkip(node) {
+      return .skipChildren
+    }
+    if let unexpected = node.unexpectedBetweenPlatformAndVersion,
+      unexpected.onlyToken(where: { $0.tokenKind == .binaryOperator(">=") }) != nil
+    {
+      addDiagnostic(
+        unexpected,
+        .versionComparisonNotNeeded,
+        fixIts: [
+          FixIt(message: RemoveNodesFixIt(unexpected), changes: .makeMissing(unexpected))
+        ],
+        handledNodes: [unexpected.id]
+      )
+    }
+    return .visitChildren
+  }
+
   public override func visit(_ node: ConditionElementSyntax) -> SyntaxVisitorContinueKind {
     if shouldSkip(node) {
       return .skipChildren
diff --git a/Sources/SwiftParserDiagnostics/ParserDiagnosticMessages.swift b/Sources/SwiftParserDiagnostics/ParserDiagnosticMessages.swift
index d0907ca85da..9d8b7feb2f6 100644
--- a/Sources/SwiftParserDiagnostics/ParserDiagnosticMessages.swift
+++ b/Sources/SwiftParserDiagnostics/ParserDiagnosticMessages.swift
@@ -212,6 +212,9 @@ extension DiagnosticMessage where Self == StaticParserError {
   public static var unexpectedSemicolon: Self {
     .init("unexpected ';' separator")
   }
+  public static var versionComparisonNotNeeded: Self {
+    .init("version comparison not needed")
+  }
 }
 
 // MARK: - Diagnostics (please sort alphabetically)
diff --git a/Tests/SwiftParserTest/translated/AvailabilityQueryTests.swift b/Tests/SwiftParserTest/translated/AvailabilityQueryTests.swift
index f41f167346c..b7fc3aae8e2 100644
--- a/Tests/SwiftParserTest/translated/AvailabilityQueryTests.swift
+++ b/Tests/SwiftParserTest/translated/AvailabilityQueryTests.swift
@@ -407,9 +407,12 @@ final class AvailabilityQueryTests: XCTestCase {
       }
       """,
       diagnostics: [
-        // TODO: (good first issue) Old parser expected error on line 1: version comparison not needed, Fix-It replacements: 19 - 22 = ''
-        DiagnosticSpec(message: "unexpected code '>= 10.51, *' in availability condition")
-      ]
+        DiagnosticSpec(message: "version comparison not needed", fixIts: ["remove '>='"])
+      ],
+      fixedSource: """
+        if #available(OSX 10.51, *) {
+        }
+        """
     )
   }
 
diff --git a/Tests/SwiftParserTest/translated/AvailabilityQueryUnavailabilityTests.swift b/Tests/SwiftParserTest/translated/AvailabilityQueryUnavailabilityTests.swift
index 8cfe667e8c8..00421bd65fb 100644
--- a/Tests/SwiftParserTest/translated/AvailabilityQueryUnavailabilityTests.swift
+++ b/Tests/SwiftParserTest/translated/AvailabilityQueryUnavailabilityTests.swift
@@ -365,8 +365,7 @@ final class AvailabilityQueryUnavailabilityTests: XCTestCase {
       }
       """,
       diagnostics: [
-        // TODO: (good first issue) Old parser expected error on line 2: version comparison not needed, Fix-It replacements: 21 - 24 = ''
-        DiagnosticSpec(message: "unexpected code '>= 10.51' in availability condition")
+        DiagnosticSpec(message: "version comparison not needed", fixIts: ["remove '>='"])
       ]
     )
   }