Thanks to its latest update, IM+ has obtained another major plus.

A popular multi-platform instant messaging app for iPhone and iPad, IM+ regularly receives updates that serve to improve its already excellent functionality. In the last couple of months alone, the app underwent two separate substantial updates.

Last June, IM+ finally got its long-overdue Retina display support for the third-generation iPad. As well, it got integrated with the Russian dating site Mamba.ru and the Chinese chat client Fetion.

Then, back in July, IM+ introduced iCloud Sync along with a new contact-merging feature called “metacontacts.”

This time, it once again gains a new significant feature.

In addition to fixing issues with Windows Live Messenger and Yahoo! authentication, the latest update to IM+ brings off-the-record (OTR) messaging.

Now available as a $4.99 in-app purchase, OTR messaging lets you have conversations with some of your contacts in complete confidence. Inspired perhaps by Gchat’s own off-the-record function, this feature encrypts and decrypts your chat messages in IM+.

Need to chat with a business partner and discuss a sensitive proposition? Want to chat with your romantic partner and exchange sweet nothings? Then OTR messaging is just the thing for you.

You can download the OTR-ready IM+ in the App Store for free. Alternatively, you can download an ad-free and more feature-rich version called IM+ Pro for $9.99.