diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index e2ed659a..b60478ab 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -22,7 +22,7 @@ jobs:
         dependencies:
           - "lowest"
           - "highest"
-        symfony-yaml: ['^3.4', '^4', '^5']
+        symfony-yaml: ['^3.4', '^4', '^5', '^6']
         include:
           - os: "windows-latest"
             php: "8.0"
@@ -36,6 +36,15 @@ jobs:
           # symfony/yaml v5 does not run on PHP 7.1
           - php: '7.1'
             symfony-yaml: '^5'
+          # symfony/yaml v6 does not run on PHP 7.*
+          - php: '7.1'
+            symfony-yaml: '^6'
+          - php: '7.2'
+            symfony-yaml: '^6'
+          - php: '7.3'
+            symfony-yaml: '^6'
+          - php: '7.4'
+            symfony-yaml: '^6'
           # symfony/yaml v3.4 is not compatible with PHP 8.0 but has no upper-bound, so it installs on it
           - php: '8.0'
             symfony-yaml: '^3.4'
diff --git a/composer.json b/composer.json
index 61bf314e..46cb26f2 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
 	"require": {
 		"php": ">=7.1.0",
 		"ext-json": "*",
-		"symfony/yaml": "^3.4 || ^4 || ^5",
+		"symfony/yaml": "^3.4 || ^4 || ^5 || ^6",
 		"justinrainbow/json-schema": "^5.2"
 	},
 	"require-dev": {
@@ -42,7 +42,7 @@
 	},
 	"extra": {
 		"branch-alias": {
-			"dev-master": "1.5.x-dev"
+			"dev-master": "1.6.x-dev"
 		}
 	},
 	"bin": [