Oh the benefits of having direct access to the source code of an Operating System hey! Samsung are wasting no time in pumping out the updates and now the Samsung Z1 has got an update Z130HDDU0BOF5 SLK, that's the one for Sri Lanka. This seems like a fair jump in version numbers from the previous Z130HDDU0BOE3, but there seems to be no obvious new features so this is mainly maintenance release for bug fixes and optimisations.
The updates for the Z1 in India and Bangladesh have not seen an update for a short while now, but hopefully they will resume soon. The Z1 is proving to be a popular handset and just the long battery life on its own is a clear winner.