diff --git a/Thanks.hooks.php b/Thanks.hooks.php
index ed0b7acb..024e8e85 100644
--- a/Thanks.hooks.php
+++ b/Thanks.hooks.php
@@ -324,8 +324,10 @@ class ThanksHooks {
 		$cssActiveClass = 'mw-thanks-flow-thank-link mw-ui-button mw-ui-quiet mw-ui-constructive';
 		$cssInactiveClass = 'mw-thanks-flow-thanked mw-ui-button mw-ui-quiet mw-ui-disabled';
 
+		$uuid = $post->getPostId()->getAlphadecimal();
+
 		// User has already thanked for revision
-		if ( $user->getRequest()->getSessionData( "flow-thanked-{$post->getPostId()}" ) ) {
+		if ( $user->getRequest()->getSessionData( "flow-thanked-{$uuid}" ) ) {
 			return Html::rawElement(
 				'span',
 				array( 'class' => $cssInactiveClass ),
@@ -344,7 +346,7 @@ class ThanksHooks {
 				'class' => $cssActiveClass,
 				'href' => '#', // TODO: No-javascript fallback
 				'title' => $tooltip,
-				'data-post-id' => $post->getPostId()
+				'data-post-id' => $uuid
 			),
 			wfMessage( 'thanks-button-thank', $user )->escaped()
 		);
diff --git a/tests/ApiFlowThankIntegrationTest.php b/tests/ApiFlowThankIntegrationTest.php
index c313da9b..5c7d91f5 100644
--- a/tests/ApiFlowThankIntegrationTest.php
+++ b/tests/ApiFlowThankIntegrationTest.php
@@ -109,7 +109,7 @@ class ApiFlowThankTest extends ApiTestCase {
 		$this->setExpectedException( 'UsageException', 'The token parameter must be set' );
 		$this->doApiRequest( array(
 			'action' => 'flowthank',
-			'postid' => UUID::create( '42' ),
+			'postid' => UUID::create( '42' )->getAlphadecimal(),
 		) );
 	}
 
@@ -121,7 +121,7 @@ class ApiFlowThankTest extends ApiTestCase {
 	public function testValidRequest(){
 		list( $result,, ) = $this->doApiRequestWithToken( array(
 			'action' => 'flowthank',
-			'postid' => $this->postByOtherUser->getPostId(),
+			'postid' => $this->postByOtherUser->getPostId()->getAlphadecimal(),
 		) );
 		$this->assertSuccess( $result );
 	}
@@ -130,7 +130,7 @@ class ApiFlowThankTest extends ApiTestCase {
 		$this->setExpectedException( 'UsageException', 'Post ID is invalid' );
 		list( $result,, ) = $this->doApiRequestWithToken( array(
 			'action' => 'flowthank',
-			'postid' => UUID::create( '42' ),
+			'postid' => UUID::create( '42' )->getAlphadecimal(),
 		) );
 	}
 
@@ -138,7 +138,7 @@ class ApiFlowThankTest extends ApiTestCase {
 		$this->setExpectedException( 'UsageException', 'You cannot thank yourself' );
 		list( $result,, ) = $this->doApiRequestWithToken( array(
 			'action' => 'flowthank',
-			'postid' => $this->postByMe->getPostId(),
+			'postid' => $this->postByMe->getPostId()->getAlphadecimal(),
 		) );
 	}