diff --git a/.gitattributes b/.gitattributes
index d153dd5..8c8edbd 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -17,3 +17,4 @@
 /features export-ignore
 /Gemfile export-ignore
 /Gemfile.lock export-ignore
+/vendor export-ignore
diff --git a/features/fixtures/symfony-2/Dockerfile b/features/fixtures/symfony-2/Dockerfile
index 53ae99c..62dd211 100644
--- a/features/fixtures/symfony-2/Dockerfile
+++ b/features/fixtures/symfony-2/Dockerfile
@@ -24,7 +24,7 @@ RUN apt-get update && \
   unzip
 
 COPY . .
-COPY --from=composer:latest /usr/bin/composer /usr/local/bin/composer
+COPY --from=composer:2.2 /usr/bin/composer /usr/local/bin/composer
 
 RUN sh setup-github-token.sh
 RUN php setup-bugsnag-config.php
diff --git a/features/fixtures/symfony-2/composer.json b/features/fixtures/symfony-2/composer.json
index 64449a8..09b8c70 100644
--- a/features/fixtures/symfony-2/composer.json
+++ b/features/fixtures/symfony-2/composer.json
@@ -23,7 +23,7 @@
     ],
     "require": {
         "php": ">=5.3.9",
-        "bugsnag/bugsnag-symfony": "dev-master as 99.99.99",
+        "bugsnag/bugsnag-symfony": "dev-main as 99.99.99",
         "doctrine/doctrine-bundle": "~1.4",
         "doctrine/orm": "^2.4.8",
         "incenteev/composer-parameter-handler": "~2.0",
diff --git a/features/fixtures/symfony-4/Dockerfile b/features/fixtures/symfony-4/Dockerfile
index 30b4a5d..7775848 100644
--- a/features/fixtures/symfony-4/Dockerfile
+++ b/features/fixtures/symfony-4/Dockerfile
@@ -24,7 +24,7 @@ RUN apt-get update && \
   unzip
 
 COPY . .
-COPY --from=composer:latest /usr/bin/composer /usr/local/bin/composer
+COPY --from=composer:2.2 /usr/bin/composer /usr/local/bin/composer
 
 RUN sh setup-github-token.sh
 RUN php setup-bugsnag-config.php
diff --git a/features/fixtures/symfony-4/composer.json b/features/fixtures/symfony-4/composer.json
index 3573d76..32910fb 100644
--- a/features/fixtures/symfony-4/composer.json
+++ b/features/fixtures/symfony-4/composer.json
@@ -14,7 +14,7 @@
         "php": ">=7.1.3",
         "ext-ctype": "*",
         "ext-iconv": "*",
-        "bugsnag/bugsnag-symfony": "dev-master as 99.99.99",
+        "bugsnag/bugsnag-symfony": "dev-main as 99.99.99",
         "composer/package-versions-deprecated": "1.11.99.4",
         "doctrine/annotations": "^1.0",
         "doctrine/doctrine-bundle": "^2.4",
diff --git a/features/fixtures/symfony-5/Dockerfile b/features/fixtures/symfony-5/Dockerfile
index 30b4a5d..7775848 100644
--- a/features/fixtures/symfony-5/Dockerfile
+++ b/features/fixtures/symfony-5/Dockerfile
@@ -24,7 +24,7 @@ RUN apt-get update && \
   unzip
 
 COPY . .
-COPY --from=composer:latest /usr/bin/composer /usr/local/bin/composer
+COPY --from=composer:2.2 /usr/bin/composer /usr/local/bin/composer
 
 RUN sh setup-github-token.sh
 RUN php setup-bugsnag-config.php
diff --git a/features/fixtures/symfony-5/composer.json b/features/fixtures/symfony-5/composer.json
index 0e502eb..9879773 100644
--- a/features/fixtures/symfony-5/composer.json
+++ b/features/fixtures/symfony-5/composer.json
@@ -16,7 +16,7 @@
         "php": ">=7.2.5",
         "ext-ctype": "*",
         "ext-iconv": "*",
-        "bugsnag/bugsnag-symfony": "dev-master as 99.99.99",
+        "bugsnag/bugsnag-symfony": "dev-main as 99.99.99",
         "composer/package-versions-deprecated": "1.11.99.2",
         "doctrine/annotations": "^1.0",
         "doctrine/doctrine-bundle": "^2.4",