diff --git a/build.gradle b/build.gradle
index 5b307987..43f4b521 100644
--- a/build.gradle
+++ b/build.gradle
@@ -114,14 +114,13 @@ ext {
     slf4jVersion = "1.7.36"
     derbyVersion = "10.15.2.0"
 
-    avroVersion = "1.11.1"
+    avroVersion = "1.8.1"
     // Version 1.8.1 brings Jackson 1.9.x/org.codehaus.jackson package for Avro and Confluent Platform 4.1.4.
     confluentPlatformVersion = "4.1.4" // For compatibility tests use version 4.1.4.
     hamcrestVersion = "2.2"
     jacksonVersion = "2.14.2" // This Jackson is used in the tests.
     jupiterVersion = "5.9.1"
-    kafkaVersion = "2.0.1" // Oldest version supported, new versions are backwards compatible.
-    jettyVersion = "11.0.14"
+    jettyVersion = "9.4.51.v20230217"
     junit4Version = "4.13.2"
     jsr305Version = "3.0.2"
     log4jVersion = "2.20.0"