diff --git a/core/kind-projector.conf b/core/kind-projector.conf
index 17c680a36..a271f97e8 100644
--- a/core/kind-projector.conf
+++ b/core/kind-projector.conf
@@ -1,10 +1,11 @@
-// https://github.com/typelevel/kind-projector.git#51ffa999d74dd8bc87b89a34da152e2d5ca08f3e
+// https://github.com/scalacommunitybuild/kind-projector.git#community-build-2.13  # was typelevel, 51ffa999
 
 // frozen (May 2021) just before an incompatible change:
 // https://github.com/typelevel/kind-projector/pull/186
+// forked (September 2021) to make tests compile under -Xsource:3
 
 vars.proj.kind-projector: ${vars.base} {
   name: "kind-projector"
-  uri: "https://github.com/typelevel/kind-projector.git#51ffa999d74dd8bc87b89a34da152e2d5ca08f3e"
+  uri: "https://github.com/scalacommunitybuild/kind-projector.git#93fabc53bbe43f19ef1e4e85d8e4a665a6fb3e1c"
 
 }
diff --git a/core/scalafix.conf b/core/scalafix.conf
index 3b117e55e..46b35b8e1 100644
--- a/core/scalafix.conf
+++ b/core/scalafix.conf
@@ -1,4 +1,7 @@
-// https://github.com/scalacenter/scalafix.git#main
+// https://github.com/scalacommunitybuild/scalafix.git#community-build-2.13  # was scalacenter, main
+
+// forked (September 2021) to remove tests that don't compile
+// under -Xsource:3
 
 vars.proj.scalafix: ${vars.base} {
   name: "scalafix"
@@ -13,4 +16,9 @@ vars.proj.scalafix: ${vars.base} {
     // of the picture anymore
     "unit"
   ]
+  extra.commands: ${vars.default-commands} [
+    // so we can still build even with -Xsource:3
+    """set testsInput / Compile / unmanagedSources / excludeFilter := HiddenFileFilter || "ConstructorProcedureSyntax.scala" || "ProcedureSyntax.scala" || "ExplicitUnit.scala" || "BetterRscCompat.scala" || "RemoveUnusedTerms.scala" || "AnnotationScopes.scala" || "NoValInForComprehension.scala" || "AnchorExpression.scala" || "AnchorMultipleRules.scala" || "NoUnitInsertion.scala""""
+    """set testsOutput / Compile / unmanagedSources / excludeFilter := HiddenFileFilter || "NoValInForComprehension.scala" || "BetterRscCompat.scala" || "RemoveUnusedTerms.scala""""
+  ]
 }
diff --git a/core/scalameta.conf b/core/scalameta.conf
index 6dea47912..4c9f54b3d 100644
--- a/core/scalameta.conf
+++ b/core/scalameta.conf
@@ -1,11 +1,13 @@
-// https://github.com/scalameta/scalameta.git#v4.4.27
+// https://github.com/scalacommunitybuild/scalameta.git#community-build-2.13  # was scalameta, v4.4.27
 
 // we typically use a tag here rather than track a branch, in the
 // interest of stability.  whatever tag scalafmt and/or scalafix expect
 
+// forked (September 2021) from v4.4.27 tag to make it compile with `-Xsource:3`
+
 vars.proj.scalameta: ${vars.base} {
   name: "scalameta"
-  uri: "https://github.com/scalameta/scalameta.git#5b978a5cc6f3f185763bb1e7d2c8888e1de8a611"
+  uri: "https://github.com/scalacommunitybuild/scalameta.git#38e8fa7fdc17a83b8edd85f76359eab2e2911387"
 
   extra.projects: ["semanticdbScalacPlugin", "testkitJVM"]
   extra.commands: ${vars.default-commands} [
diff --git a/core/wartremover.conf b/core/wartremover.conf
index 73296bd2c..2e51f4d51 100644
--- a/core/wartremover.conf
+++ b/core/wartremover.conf
@@ -2,7 +2,7 @@
 
 vars.proj.wartremover: ${vars.base} {
   name: "wartremover"
-  uri: "https://github.com/wartremover/wartremover.git#c43465833bfb6aa150c54ec590b3da8599531c40"
+  uri: "https://github.com/wartremover/wartremover.git#72e4fe0dff3ff4021dd816d231bb69ba0a99a7f8"
 
   extra.exclude: [
     "sbt-plugin"
@@ -10,4 +10,9 @@ vars.proj.wartremover: ${vars.base} {
   ]
   deps.ignore: ["org.scala-sbt#scripted-plugin"]
   check-missing: false
+  extra.commands: ${vars.default-commands} [
+    // we exclude these test sources because they contain code that fails to compile under
+    // -Xsource:3 (which we want to be able to test in the community build)
+    """set core / Test / unmanagedSources / excludeFilter := HiddenFileFilter || "StringPlusAnyTest.scala" || "UnsafeTest.scala""""
+  ]
 }