diff --git a/build.gradle b/build.gradle
index 3170fb0595..b7dcc8227b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -117,8 +117,15 @@ buildscript {
     ext.picocli_version = '3.9.6'
     ext.commons_io_version = '2.6'
     ext.controlsfx_version = '8.40.15'
-    ext.fontawesomefx_commons_version = '11.0'
-    ext.fontawesomefx_fontawesome_version = '4.7.0-11'
+    if (JavaVersion.current() == JavaVersion.VERSION_11) {
+        // has been compiled by a more recent version of the Java Runtime (class file version 55.0)
+        ext.fontawesomefx_commons_version = '11.0'
+        ext.fontawesomefx_fontawesome_version = '4.7.0-11'
+    }
+    else {
+        ext.fontawesomefx_commons_version = '8.15'
+        ext.fontawesomefx_fontawesome_version = '4.7.0-5'
+    }
 
     // Name of the IntelliJ SDK created for the deterministic Java rt.jar.
     // ext.deterministic_idea_sdk = '1.8 (Deterministic)'