diff --git a/composer.json b/composer.json
index f08d7df..ce412a2 100644
--- a/composer.json
+++ b/composer.json
@@ -31,12 +31,6 @@
         "phpstan/phpstan-deprecation-rules": "^1.0",
         "phpstan/phpstan-strict-rules": "^1.3"
     },
-    "repositories": [
-        {
-            "type": "git",
-            "url": "https://github.com/roundcube/roundcubemail.git"
-        }
-    ],
     "minimum-stability": "dev",
     "prefer-stable": true,
     "autoload": {
diff --git a/src/ExtensionInstaller.php b/src/ExtensionInstaller.php
index 8cfbd61..5d0ca1a 100644
--- a/src/ExtensionInstaller.php
+++ b/src/ExtensionInstaller.php
@@ -73,10 +73,11 @@ private function initializeRoundcubemailEnvironment(): void
     public function install(InstalledRepositoryInterface $repo, PackageInterface $package)
     {
         $this->setRoundcubemailInstallPath($repo);
-        $this->initializeRoundcubemailEnvironment();
-        $this->rcubeVersionCheck($package);
 
         $postInstall = function () use ($package) {
+            $this->initializeRoundcubemailEnvironment();
+            $this->rcubeVersionCheck($package);
+
             $config_file = $this->rcubeConfigFile();
             $package_name = $this->getPackageName($package);
             $package_dir = $this->getInstallPath($package);
@@ -134,20 +135,21 @@ public function install(InstalledRepositoryInterface $repo, PackageInterface $pa
     public function update(InstalledRepositoryInterface $repo, PackageInterface $initial, PackageInterface $target)
     {
         $this->setRoundcubemailInstallPath($repo);
-        $this->initializeRoundcubemailEnvironment();
-        $this->rcubeVersionCheck($target);
 
-        $extra = $target->getExtra();
-        $fs = new Filesystem();
+        $postUpdate = function () use ($initial, $target) {
+            $this->initializeRoundcubemailEnvironment();
+            $this->rcubeVersionCheck($target);
+
+            $extra = $target->getExtra();
+            $fs = new Filesystem();
 
-        // backup persistent files e.g. config.inc.php
-        $package_dir = $this->getInstallPath($initial);
-        $temp_dir = $package_dir . '-' . sprintf('%010d%010d', mt_rand(), mt_rand());
+            // backup persistent files e.g. config.inc.php
+            $package_dir = $this->getInstallPath($initial);
+            $temp_dir = $package_dir . '-' . sprintf('%010d%010d', mt_rand(), mt_rand());
 
-        // make a backup of existing files (for restoring persistent files)
-        $fs->copy($package_dir, $temp_dir);
+            // make a backup of existing files (for restoring persistent files)
+            $fs->copy($package_dir, $temp_dir);
 
-        $postUpdate = function () use ($target, $extra, $fs, $temp_dir) {
             $package_name = $this->getPackageName($target);
             $package_dir = $this->getInstallPath($target);
 
@@ -199,11 +201,12 @@ public function update(InstalledRepositoryInterface $repo, PackageInterface $ini
     public function uninstall(InstalledRepositoryInterface $repo, PackageInterface $package)
     {
         $this->setRoundcubemailInstallPath($repo);
-        $this->initializeRoundcubemailEnvironment();
 
-        $config = $this->composer->getConfig()->get('roundcube');
+        $postUninstall = function () use ($package) {
+            $this->initializeRoundcubemailEnvironment();
+
+            $config = $this->composer->getConfig()->get('roundcube');
 
-        $postUninstall = function () use ($package, $config) {
             // post-uninstall: deactivate package
             $package_name = $this->getPackageName($package);
             $package_dir = $this->getInstallPath($package);
diff --git a/test-composer/composer.json b/test-composer/composer.json
index cd3533a..d3e8bbe 100644
--- a/test-composer/composer.json
+++ b/test-composer/composer.json
@@ -1,13 +1,10 @@
 {
     "name": "roundcube/plugin-installer-test",
     "require": {
-        "roundcube/carddav": "^4 || ^5"
+        "roundcube/carddav": "^4 || ^5",
+        "roundcube/roundcubemail": "dev-master as 1.99"
     },
     "repositories": [
-        {
-            "type": "git",
-            "url": "https://github.com/roundcube/roundcubemail.git"
-        },
         {
             "type": "path",
             "url": ".."