diff --git a/demo/client.ts b/demo/client.ts
index adbbd85a..b2468ec3 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -736,7 +736,7 @@ function powerlineSymbolTest() {
 
 function addDecoration() {
   term.options['overviewRulerWidth'] = 15;
-  const marker = term.addMarker(1);
+  const marker = term.registerMarker(1);
   const decoration = term.registerDecoration({
     marker,
     backgroundColor: '#00FF00',
@@ -751,13 +751,13 @@ function addDecoration() {
 
 function addOverviewRuler() {
   term.options['overviewRulerWidth'] = 15;
-  term.registerDecoration({marker: term.addMarker(1), overviewRulerOptions: { color: '#ef2929' }});
-  term.registerDecoration({marker: term.addMarker(3), overviewRulerOptions: { color: '#8ae234' }});
-  term.registerDecoration({marker: term.addMarker(5), overviewRulerOptions: { color: '#729fcf' }});
-  term.registerDecoration({marker: term.addMarker(7), overviewRulerOptions: { color: '#ef2929', position: 'left' }});
-  term.registerDecoration({marker: term.addMarker(7), overviewRulerOptions: { color: '#8ae234', position: 'center' }});
-  term.registerDecoration({marker: term.addMarker(7), overviewRulerOptions: { color: '#729fcf', position: 'right' }});
-  term.registerDecoration({marker: term.addMarker(10), overviewRulerOptions: { color: '#8ae234', position: 'center' }});
-  term.registerDecoration({marker: term.addMarker(10), overviewRulerOptions: { color: '#ffffff80', position: 'full' }});
+  term.registerDecoration({marker: term.registerMarker(1), overviewRulerOptions: { color: '#ef2929' }});
+  term.registerDecoration({marker: term.registerMarker(3), overviewRulerOptions: { color: '#8ae234' }});
+  term.registerDecoration({marker: term.registerMarker(5), overviewRulerOptions: { color: '#729fcf' }});
+  term.registerDecoration({marker: term.registerMarker(7), overviewRulerOptions: { color: '#ef2929', position: 'left' }});
+  term.registerDecoration({marker: term.registerMarker(7), overviewRulerOptions: { color: '#8ae234', position: 'center' }});
+  term.registerDecoration({marker: term.registerMarker(7), overviewRulerOptions: { color: '#729fcf', position: 'right' }});
+  term.registerDecoration({marker: term.registerMarker(10), overviewRulerOptions: { color: '#8ae234', position: 'center' }});
+  term.registerDecoration({marker: term.registerMarker(10), overviewRulerOptions: { color: '#ffffff80', position: 'full' }});
 }
 
diff --git a/src/browser/public/Terminal.ts b/src/browser/public/Terminal.ts
index 6898af36..53904cf9 100644
--- a/src/browser/public/Terminal.ts
+++ b/src/browser/public/Terminal.ts
@@ -160,7 +160,6 @@ export class Terminal implements ITerminalApi {
     this._core.deregisterCharacterJoiner(joinerId);
   }
   public registerMarker(cursorYOffset: number = 0): IMarker | undefined {
-    this._checkProposedApi();
     this._verifyIntegers(cursorYOffset);
     return this._core.addMarker(cursorYOffset);
   }
@@ -169,9 +168,6 @@ export class Terminal implements ITerminalApi {
     this._verifyPositiveIntegers(decorationOptions.x ?? 0, decorationOptions.width ?? 0, decorationOptions.height ?? 0);
     return this._core.registerDecoration(decorationOptions);
   }
-  public addMarker(cursorYOffset: number): IMarker | undefined {
-    return this.registerMarker(cursorYOffset);
-  }
   public hasSelection(): boolean {
     return this._core.hasSelection();
   }
diff --git a/typings/xterm-headless.d.ts b/typings/xterm-headless.d.ts
index c840ed09..93029c6f 100644
--- a/typings/xterm-headless.d.ts
+++ b/typings/xterm-headless.d.ts
@@ -630,18 +630,13 @@ declare module 'xterm-headless' {
     resize(columns: number, rows: number): void;
 
     /**
-     * (EXPERIMENTAL) Adds a marker to the normal buffer and returns it. If the
-     * alt buffer is active, undefined is returned.
+     * Adds a marker to the normal buffer and returns it. If the alt buffer is
+     * active, undefined is returned.
      * @param cursorYOffset The y position offset of the marker from the cursor.
      * @returns The new marker or undefined.
      */
     registerMarker(cursorYOffset?: number): IMarker | undefined;
 
-    /**
-     * @deprecated use `registerMarker` instead.
-     */
-    addMarker(cursorYOffset: number): IMarker | undefined;
-
     /*
       * Disposes of the terminal, detaching it from the DOM and removing any
       * active listeners.
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index b6bb0fda..adfc3f54 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -912,18 +912,13 @@ declare module 'xterm' {
     deregisterCharacterJoiner(joinerId: number): void;
 
     /**
-     * (EXPERIMENTAL) Adds a marker to the normal buffer and returns it. If the
-     * alt buffer is active, undefined is returned.
+     * Adds a marker to the normal buffer and returns it. If the alt buffer is
+     * active, undefined is returned.
      * @param cursorYOffset The y position offset of the marker from the cursor.
      * @returns The new marker or undefined.
      */
     registerMarker(cursorYOffset?: number): IMarker | undefined;
 
-    /**
-     * @deprecated use `registerMarker` instead.
-     */
-    addMarker(cursorYOffset: number): IMarker | undefined;
-
     /**
      * (EXPERIMENTAL) Adds a decoration to the terminal using
      *  @param decorationOptions, which takes a marker and an optional anchor,