The Samsung Z1 has had a fast and steady flow of software / firmware updates for it, the last one only being 3 weeks ago (Z130HDDU0BOC7). Today their is a 17.3Mb update, which updates your Z1 to firmware version Z130HDDU0BOD7. There is no change log at present, but early reports suggest it helps with device stability and online mail services.
A shortcut for the new WhatsApp app has been included with WhatsApp being updated to version 2.11.17 (04/18/2015). After you download and Install the official version of WhatsApp, the previous version will be disabled. The App also now supports 14 languages. This update has been reported to be released in India at the moment, no news on the Bangladesh release at the moment, but previously there was a two week delay.
If you do not get a automatically prompted to update your firmware, you can manually check by using the steps below: