diff --git a/modules/CommentController.js b/modules/CommentController.js
index 62d6b590a..a8eaa40b6 100644
--- a/modules/CommentController.js
+++ b/modules/CommentController.js
@@ -1,5 +1,5 @@
 var
-	api = new mw.Api( { formatversion: 2 } ),
+	api = new mw.Api( { parameters: { formatversion: 2 } } ),
 	controller = require( './controller.js' ),
 	modifier = require( './modifier.js' ),
 	parser = require( './parser.js' ),
@@ -374,7 +374,7 @@ CommentController.prototype.save = function ( parsoidData ) {
 			{
 				// No timeout. Huge talk pages take a long time to save, and falsely reporting an error can
 				// result in duplicate messages when the user retries. (T249071)
-				api: new mw.Api( { ajax: { timeout: 0 }, formatversion: 2 } )
+				api: new mw.Api( { ajax: { timeout: 0 }, parameters: { formatversion: 2 } } )
 			}
 		).catch( function ( code, data ) {
 			// Handle edit conflicts. Load the latest revision of the page, then try again. If the parent
diff --git a/modules/controller.js b/modules/controller.js
index 7a247b4b0..c194cf93b 100644
--- a/modules/controller.js
+++ b/modules/controller.js
@@ -1,7 +1,7 @@
 'use strict';
 
 var
-	api = new mw.Api( { formatversion: 2 } ),
+	api = new mw.Api( { parameters: { formatversion: 2 } } ),
 	$pageContainer,
 	parser = require( './parser.js' ),
 	utils = require( './utils.js' ),
diff --git a/modules/dt.ui.ReplyWidget.js b/modules/dt.ui.ReplyWidget.js
index 083746b67..55c6ea43f 100644
--- a/modules/dt.ui.ReplyWidget.js
+++ b/modules/dt.ui.ReplyWidget.js
@@ -94,7 +94,7 @@ function ReplyWidget( commentController, parsoidData, config ) {
 	this.beforeUnloadHandler = this.onBeforeUnload.bind( this );
 	this.unloadHandler = this.onUnload.bind( this );
 
-	this.api = new mw.Api( { formatversion: 2 } );
+	this.api = new mw.Api( { parameters: { formatversion: 2 } } );
 	this.onInputChangeThrottled = OO.ui.throttle( this.onInputChange.bind( this ), 1000 );
 
 	// Initialization
@@ -525,7 +525,6 @@ ReplyWidget.prototype.onReplyClick = function () {
 				titles: mw.config.get( 'wgRelevantPageName' )
 			} ).then( function () {
 				return widget.api.get( {
-					formatversion: 2,
 					action: 'parse',
 					prop: [ 'text', 'modules', 'jsconfigvars' ],
 					page: mw.config.get( 'wgRelevantPageName' )
diff --git a/modules/dt.ui.UsernameCompletion.js b/modules/dt.ui.UsernameCompletion.js
index ef55eb804..787a56cad 100644
--- a/modules/dt.ui.UsernameCompletion.js
+++ b/modules/dt.ui.UsernameCompletion.js
@@ -20,7 +20,7 @@ function MWUsernameCompletionAction( surface ) {
 	// Parent constructor
 	MWUsernameCompletionAction.super.call( this, surface );
 
-	this.api = new mw.Api( { formatversion: 2 } );
+	this.api = new mw.Api( { parameters: { formatversion: 2 } } );
 	this.searchedPrefixes = {};
 	this.localUsers = [];
 	this.ipUsers = [];