diff --git a/client/src/main/java/io/pravega/keycloak/client/KeycloakAuthzClient.java b/client/src/main/java/io/pravega/keycloak/client/KeycloakAuthzClient.java
index 9ea6ae6..9196476 100644
--- a/client/src/main/java/io/pravega/keycloak/client/KeycloakAuthzClient.java
+++ b/client/src/main/java/io/pravega/keycloak/client/KeycloakAuthzClient.java
@@ -199,7 +199,7 @@ public void update(AuthorizationResponse response) {
         }
 
         boolean isTokenTimeToLiveSufficient() {
-            return token.getExpiration() - tokenMinimumTimeToLiveSecs > Time.currentTime();
+            return token.getExp() - tokenMinimumTimeToLiveSecs > Time.currentTime();
         }
     }
 
diff --git a/client/src/test/java/io/pravega/keycloak/client/helpers/AccessTokenIssuer.java b/client/src/test/java/io/pravega/keycloak/client/helpers/AccessTokenIssuer.java
index 0d85301..388b05d 100644
--- a/client/src/test/java/io/pravega/keycloak/client/helpers/AccessTokenIssuer.java
+++ b/client/src/test/java/io/pravega/keycloak/client/helpers/AccessTokenIssuer.java
@@ -15,6 +15,7 @@
 import org.keycloak.common.util.KeyUtils;
 import org.keycloak.jose.jws.JWSBuilder;
 import org.keycloak.representations.AccessToken;
+import org.keycloak.common.crypto.CryptoIntegration;
 
 import java.security.KeyPair;
 import java.security.PublicKey;
@@ -32,6 +33,7 @@ public class AccessTokenIssuer implements PublicKeyLocator {
     private final KeyPair issuerKeyPair;
 
     public AccessTokenIssuer() {
+        CryptoIntegration.init(null);
         issuerKeyPair = KeyUtils.generateRsaKeyPair(2048);
     }
 
@@ -71,7 +73,7 @@ public String issue(AccessToken accessToken) {
      * @return
      */
     private static int computeExpiration(AccessToken token, Duration expiration) {
-        int issuedAt = token.getIssuedAt();
+        int issuedAt = token.getIat().intValue();
         int expirationInSeconds = (int) expiration.toMillis() / 1000;
         return issuedAt + expirationInSeconds;
     }
diff --git a/gradle.properties b/gradle.properties
index fc62866..59c1aec 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -12,7 +12,7 @@
 
 guavaVersion=28.2-jre
 junitVersion=4.13.2
-keycloakVersion=15.1.1
+keycloakVersion=19.0.3
 mockitoVersion=3.3.3
 pravegaVersion=0.12.0
 slf4jVersion=1.7.30