Cannot run 64 bit Intraweb app on older server (2012R2) since Delphi 11.3

[rudyPos]

This may be a combination of Embarcadero Technologies Delphi and Intraweb

iw 15.x

A) I have a web server application compiled as WIN64 that was running successfully on Server 2012R2
B) Delphi was updated to 11.3 from 11.2. - web server application recompiled and runs successfully tested
on Win 10 (my Delphi PC).
C) copy updated exe compiled under 11.3 to target server - Application does not start 'app crash'.
D) copy app in 11.3 as 32 bit app = runs on Server 2012R2
E) a non Intraweb app in 11.3 as 64 bit does RUN on Server 2012R2.

Any ideas? The only setting in project options I have modified is PE header info, bu this made no difference,
and did not need to be changed for the non-IW app.

Thanks in advance

[rudyPos]

Previous was 15.3.0 and 15.3.3 (did not use 15.3.4)
Notice-I just updated to iw15.3.5, and the 64 bit IW app now works,

not sure what the issue is - was

regards

[Alexandre Machado]

Old behavior restored in 15.3.4:

-> zlib x64 compatibility with older processors (no AVX instructions) restored. This regression bug has been introduced in IW 15.3.0 and won’t affect older builds.

This was caused by ASM instructions incompatible with older hardware (not the OS itself).