diff --git a/build.sc b/build.sc
index aa08a76d39f..7c887576e6b 100755
--- a/build.sc
+++ b/build.sc
@@ -33,7 +33,8 @@ object Settings {
     "0.9.8",
     "0.9.9",
     "0.10.0-M2",
-    "0.10.0-M3"
+    "0.10.0-M3",
+    "0.10.0-M4"
   )
   val mimaBaseVersions = Seq("0.10.0-M3")
 }
diff --git a/docs/antora/antora.yml b/docs/antora/antora.yml
index 8639fb2b511..521b31fcc53 100644
--- a/docs/antora/antora.yml
+++ b/docs/antora/antora.yml
@@ -1,12 +1,12 @@
 name: mill
 title: Mill Documentation
-version: '0.10.0-M3'
+version: '0.10.0-M4'
 nav:
   - modules/ROOT/nav.adoc
 asciidoc:
   attributes:
-    mill-version: '0.10.0-M3'
-    mill-last-tag: '0.10.0-M3'
+    mill-version: '0.10.0-M4'
+    mill-last-tag: '0.10.0-M4'
     bsp-version: '2.0.0'
     example-semanticdb-version: '4.4.29'
     example-scala-version: '2.13.7'
diff --git a/readme.adoc b/readme.adoc
index 14f533345be..f685705dd45 100644
--- a/readme.adoc
+++ b/readme.adoc
@@ -209,12 +209,33 @@ corresponding version of Mill.
 
 === 'main' branch
 :version: main
+:prev-version: 0.10.0-M4
+:milestone: 55
+:milestone-name: after 0.10.0-M4
+
+_Changes since {prev-version}:_
+
+_For details refer to
+{link-milestone}/{milestone}?closed=1[milestone {milestone-name}]
+and the {link-compare}/{prev-version}\...{version}[list of commits]._
+
+
+=== 0.10.0-M4 - 2021-11-08
+:version: 0.10.0-M4
 :prev-version: 0.10.0-M3
 :milestone: 54
-:milestone-name: after 0.10.0-M3
+:milestone-name: 0.10.0-M4
 
 _Changes since {prev-version}:_
 
+* BSP support rework and overhaul of built-in BSP server
+* GenIdea: failures when inspecting and resolving the build are not properly reported
+* Coursier: we now implemented a workaround to tackle concurrent downloads issues
+* New `--import` cmdline option to run ad-hoc plugins without editing of `build.sc`
+* New `T.ctx().workspace` API to access the project root directory
+* Various internal improvements and bug fixes
+* Various refactorings and cleanups
+
 _For details refer to
 {link-milestone}/{milestone}?closed=1[milestone {milestone-name}]
 and the {link-compare}/{prev-version}\...{version}[list of commits]._