Whats App 2.0 was released with a messaging component and the number of active users suddenly increased to 250,000.
Acton was still unemployed and managing another startup, and he decided to join the company.
In January 2010, support for Black Berry smartphones was added, and subsequently for Symbian OS in May 2010 and for Android OS in August 2010.
In August 2011 a beta for Nokia's non-smartphone OS Series 40 was added.
Whats App was officially made available for PCs through a web client, under the name Whats App Web, in late January 2015 through an announcement made by Koum on his Facebook page: "Our web client is simply an extension of your phone: the web browser mirrors conversations and messages from your mobile device—this means all of your messages still live on your phone".
The Whats App user's handset must still be connected to the Internet for the browser application to function.
In August 2014, Whats App released an update to its Android app, adding support for Android Wear smartwatches.
In December 2009, the ability to send photos was added to Whats App for the i Phone. Facebook, which was advised by Allen & Co, paid billion in cash, billion in Facebook shares, and (advised by Morgan Stanley) an additional billion in restricted stock units granted to Whats App's founders, Koum and Acton.Whats App introduces a feature named Read Receipts, which alerts senders when their messages are read by recipients.Within a week, Whats App introduces an update allowing users to disable this feature so that message recipients do not send acknowledgements.Diego Dzodan, a Facebook executive, is arrested by Brazilian federal police after Facebook fails to turn over information from his Whats App messaging account into a judge's request for a drug trafficking investigation.The application runs from a mobile device though it is also accessible from desktop computers; the service uses standard cellular mobile numbers.