diff --git a/decoder/build.gradle b/decoder/build.gradle
index edd8dfa..a3f4dfb 100644
--- a/decoder/build.gradle
+++ b/decoder/build.gradle
@@ -45,6 +45,7 @@ dependencies {
     implementation Deps.kotlin_reflect
     implementation Deps.java_cose
     implementation Deps.json_validation
+    implementation Deps.json_validation_rhino
     implementation Deps.jackson_cbor
     implementation Deps.bouncy_castle
 
diff --git a/decoder/src/main/java/dgca/verifier/app/decoder/JsonSchema.kt b/decoder/src/main/java/dgca/verifier/app/decoder/JsonSchema.kt
index c2c3ece..be76df0 100644
--- a/decoder/src/main/java/dgca/verifier/app/decoder/JsonSchema.kt
+++ b/decoder/src/main/java/dgca/verifier/app/decoder/JsonSchema.kt
@@ -51,7 +51,7 @@ const val JSON_SCHEMA_V1 = "{\n" +
         "      \"title\": \"Date of birth\",\n" +
         "      \"description\": \"Date of Birth of the person addressed in the DGC. ISO 8601 date format restricted to range 1900-2099\",\n" +
         "      \"type\": \"string\",\n" +
-        "      \"format\": \"date\",\n" +
+        "      \"pattern\": \"^(19|20)\\\\d{2}(-\\\\d{2}(-\\\\d{2}(T\\\\d{2}:\\\\d{2}:\\\\d{2})?)?)?\$\",\n" +
         "      \"examples\": [\n" +
         "        \"1979-04-14\"\n" +
         "      ]\n" +