My wallet 1.2.4 is also stuck @ 250169. I had that problem right after the update, so I deleted the burst_db folder and let it redownload the whole blockchain. Now it's stuck again :|
Some users have stability issues with the core version 1.2.4. We are working on a solution and release a fix as soon as possible.
The core version 1.2.3 still works and will work after Block 255000 but the Blockchain has to be synced all over again unfortunately.
There also seems to be an issue with connecting to updated clients. Since I have upgraded to 1.2.4 I seem to only connect to outdated 1.2.3 clients with the occasional 1.2.4. I deleted my dB and reused the latest chain download but I still cannot get up-to-date. Burst.ninja still appears to be using the 1.2.3 version.