diff --git a/pom.xml b/pom.xml
index b5d7871..9a0d488 100644
--- a/pom.xml
+++ b/pom.xml
@@ -15,7 +15,7 @@
 	</licenses>
 
 	<properties>
-		<vertx.version>4.0.0</vertx.version>
+		<vertx.version>3.8.0</vertx.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 		<java.version>11</java.version>
diff --git a/src/main/java/org/folio/ncip/FolioNcipHelper.java b/src/main/java/org/folio/ncip/FolioNcipHelper.java
index ca1b32d..4ae5211 100644
--- a/src/main/java/org/folio/ncip/FolioNcipHelper.java
+++ b/src/main/java/org/folio/ncip/FolioNcipHelper.java
@@ -54,7 +54,7 @@ public class FolioNcipHelper {
 
 	public FolioNcipHelper(Promise<Void> promise) {
 		Future<Void> steps = initToolkitDefaults();
-		steps.onComplete(ar -> {
+			steps.setHandler(ar -> {
 			if (ar.succeeded()) {
 				promise.complete();
 			} else {