A: The current version of Nitro browser still serves its purpose well, be the fastest browser in the world. Therefore, we don't have the plan to update it in the short term but any suggestions and feedback are more than welcome.
As for Maxthon for WP and Linux, they still run well and smooth. And resources at Maxthon are focused on Maxthon5 for Windows, Android, iOS and Mac at this moment. Therefore updates are not coming very soon.
If you run into issues with these versions, feel free to contact our support team at http://www.maxthon.com/mx/bug/post/.