While Viber may not have plans on supporting a BlackBerry 10 application, they've gone ahead and rolled out an update to their application for BBOS devices. Not only does it bring bux fixes and improvements but Twitter support and increased group capacity.

If you are a current user, the full list of changes and additions are shown below. 

New Features

  • Sending multiple emoticons in the same message
  • Faster message delivery
  • Increased group capacity (up to 100 participants)
  • Twitter integration, allowing photo sharing on Twitter and "Tweet about Viber"
  • Bug fixes and performance improvements

It may take some time before the update populates BlackBerry World, however, you can grab the latest version at the link below.

More information/Download Viber