The Nokia Lumia 925 launched with a new and improved software and Nokia promised to make it available to its older WP8 phones in the summer with the so-called Amber update. Now we've got a more concrete time frame thanks to the Nokia Spain's Twitter account.
The Amber update for Nokia Lumia range with WP8 arrive in August giving the same user experience as #Lumia925
Translated with Google Translate
The Amber update will bring the new Smart Camera lens for Lumia, which does post processing tricks like Action shot, Motion focus and object removal. Check out demos of those effects here.
There’s more - Amber will enable the FM radio receiver that has been lying dormant in Windows Phone 8 powered Lumia phones (except the 620) and the "double tap to wake" lockscreen with a clock (presumably only for AMOLED packing phones). Check out our preview of the Lumia 925 for more details on these features.
By the way, Twitter accounts aren't 100% reliable when it comes to such information, so we're still waiting for official confirmation.
Source (in Spanish) | Via (in Italian)