Windows Phone Store and app update

Question

Windows phone

Probably, I'm looking badly, but I can't find in any way whether a Windows Phone application is subject to a second review procedure when its update is released, and not the first version.

This is of interest for two reasons:
1. Can attackers add harmful functionality in the new version, stop following design guidelines, etc. and avoid verification?
2. Should I do not frequent small updates, but larger, but rare ones, so as not to wait for the end of long verification procedures?

Thank you!

Answer 1

Updates undergo a full certification procedure

Answer 2

It is optimal to release an update every month or two