diff --git a/CHANGELOG.md b/CHANGELOG.md
index abc406f..1cd65a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,5 @@
+## 0.5.0
+*  compatible with rcoq9 + coq package (#57 by @thery)
 ## 0.4.1
 * Change in the xml-protocol (#811 by @thery)
 ## 0.4.0
diff --git a/package-lock.json b/package-lock.json
index 0a0b7f0..a80673f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "vscoq1",
-  "version": "0.4.1",
+  "version": "0.5.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "vscoq1",
-      "version": "0.4.1",
+      "version": "0.5.0",
       "license": "MIT",
       "dependencies": {
         "@types/hyperscript": "^0.0.4",
diff --git a/package.json b/package.json
index 352a867..5266333 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,7 @@
     "email": "siegebell@gmail.com",
     "url": "http://people.csail.mit.edu/cj/"
   },
-  "version": "0.4.1",
+  "version": "0.5.0",
   "publisher": "coq-community",
   "license": "MIT",
   "icon": "images/logo.png",
diff --git a/server/src/coqtop/CoqTop.ts b/server/src/coqtop/CoqTop.ts
index c7ddb4e..2b9ff5f 100644
--- a/server/src/coqtop/CoqTop.ts
+++ b/server/src/coqtop/CoqTop.ts
@@ -102,7 +102,7 @@ export function detectVersion(coqtopModule: string, cwd: string, console?: {log:
       });
 
       coqtop.on('close', () => {
-        const ver = /^\s*The Coq Proof Assistant, version (.+?)\s/.exec(result);
+        const ver = /^\s*The (?:Coq Proof Assistant|Rocq Prover), version (.+?)\s/.exec(result);
         // if(!ver)
         //   console.warn('Could not detect coqtop version');
         resolve(!ver ? undefined : ver[1]);
diff --git a/server/src/coqtop/CoqTop8.ts b/server/src/coqtop/CoqTop8.ts
index 35f7174..9cbfc87 100644
--- a/server/src/coqtop/CoqTop8.ts
+++ b/server/src/coqtop/CoqTop8.ts
@@ -227,6 +227,10 @@ export class CoqTop extends IdeSlave8 implements coqtop.CoqTop {
     }
     if (semver.satisfies(this.coqtopVersion, ">= 8.9")) {
       var coqtopModule = this.coqidetopBin;
+      if (semver.satisfies(this.coqtopVersion, ">= 9.0")) {
+        // with rocq not .opt
+        coqtopModule = coqtopModule.replace(/(.opt)$/, '');
+      }
       // var coqtopModule = 'cmd';
       var args = [
         // '/D /C', this.coqPath + '/coqtop.exe',