diff --git a/build.gradle b/build.gradle
index 0d328cf..2045d5a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -38,7 +38,7 @@
     asmVersion = '9.2'  // When updating update tools/asmifier.py and Toolhelper as well.
     espressoVersion = '3.0.0'
     fastutilVersion = '7.2.0'
-    guavaVersion = '31.0.1-jre'
+    guavaVersion = '30.1.1-jre'
     joptSimpleVersion = '4.6'
     gsonVersion = '2.7'
     junitVersion = '4.13-beta-2'