A small firmware update has been released for the Sony Xperia Z3+ (E6553), which moves the build number from 28.0.A.7.27 to version 28.0.A.7.31. The update has been released OTA in select regions such as Hong Kong and is available via PC Companion in Taiwan. If you have updated, let us know what changes you’ve noticed below.
Update: As noted in the comments below, the update provides a fix to the Stagefright exploit.
Thanks Connor and Haziq!