It seems like updates are raining for Lumia devices one after another. Tango’s build 8773 has started rolling for Lumia 710 and 800 from 27th June. And already a new Tango build has appeared on the NaviFirm for 610 and 710.
For your info Lumia 610 is shipped with pre-installed Tango build 8773. So now it seems that all the Lumia devices running Tango 8773 will get updated to Tango 8779 in due course. Check the screenshots above for Tango 8779 build availability for Lumia 610 and 710 on naviFirm.
Changelog for 8779 is not known, but according to “blogosphere” it seems to bring few changes like “Location icon” to your device and may be some bug fixes.