diff --git a/org.lflang.epoch.external.dependencies/pom.xml b/org.lflang.epoch.external.dependencies/pom.xml
index 45bc12f..f3e3e00 100644
--- a/org.lflang.epoch.external.dependencies/pom.xml
+++ b/org.lflang.epoch.external.dependencies/pom.xml
@@ -19,6 +19,16 @@
       <artifactId>kotlin-stdlib</artifactId>
       <version>${kotlin-version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.json</groupId>
+      <artifactId>json</artifactId>
+      <version>${jsonVersion}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.antlr</groupId>
+      <artifactId>antlr4-runtime</artifactId>
+      <version>${antlr4Version}</version>
+    </dependency>
   </dependencies>
 
   <build>
diff --git a/pom.xml b/pom.xml
index 6aee5a8..ce9356f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -16,6 +16,12 @@
     <eclipse-url>https://download.eclipse.org/releases/latest</eclipse-url>
 
     <kotlin-version>1.6.20</kotlin-version>
+
+    <!-- JSON version used in the LF Verifier -->
+    <jsonVersion>20230618</jsonVersion>
+
+    <!-- ANTLR4 version used in the LF Verifier (not the one used in xtext) -->
+    <antlr4Version>4.7.2</antlr4Version>
   </properties>
 
   <modules>