There is a Gmail update available in the Google Play store, but it is unclear what it changes. There is a changelog on its app page that lists "Security update," however, the version number (2.3.5.2) doesn't matchup to what I show on my Galaxy Nexus. I compared this new 4.0.5 to 4.0.4 and the differences are so subtle that you may not even be able to tell. Assuming that it's nothing major and probably is a security update.
Update:
