diff --git a/deps.edn b/deps.edn
index 18d0874..2070ea2 100644
--- a/deps.edn
+++ b/deps.edn
@@ -20,7 +20,7 @@
                       io.github.cognitect-labs/test-runner
                       {:git/tag "v0.5.0" :git/sha "48c3c67"}
                       ;; connection pooling
-                      ;; 5.0.0 requires JDK with class type 55:
+                      ;; 5.0.0 is not compatible with JDK 8:
                       com.zaxxer/HikariCP {:mvn/version "3.4.2"}
                       com.mchange/c3p0 {:mvn/version "0.9.5.5"}
                       ;; JDBC drivers
@@ -29,7 +29,8 @@
                       ;; compatible only with JDK9+:
                       ;; org.apache.derby/derby {:mvn/version "10.15.2.0"}
                       ;; org.apache.derby/derbyshared {:mvn/version "10.15.2.0"}
-                      org.hsqldb/hsqldb {:mvn/version "2.6.1"}
+                      ;; 2.6.1 is not compatible with JDK 8:
+                      org.hsqldb/hsqldb {:mvn/version "2.5.0"}
                       com.h2database/h2 {:mvn/version "1.4.200"}
                       net.sourceforge.jtds/jtds {:mvn/version "1.3.1"}
                       org.mariadb.jdbc/mariadb-java-client {:mvn/version "2.7.4"}