If your Acer phone has stopped updating itself, it is highly likely that the manufacturer has stopped supporting its automatic update. But, usually, after that, craftsmen from different countries create alternative firmware that allows you to update the android version to a newer or more stable one, or add some features.
To find instructions for updating Acer, use the search form below:
If your model is not in the list of search results, write in the comments, we will make an answer and send a link.