Program works with older libssl, but not with newer

[Christoph Pleger]

Hello,

I have here a self-written server program and the corresponding self-written 
client program. These run well together with libssl 1.1.0l, but with libssl 
1.1.1d, the same programs give errors SSL_ERROR_SYSCALL in SSL_read(), no 
matter if I recompile the programs and then run them, or just replace libssl 
with the newer version. 

So, I want to ask if there are any known incompabilities in the libssl 
versions that require me to change the code of the programs, or if there is 
any known bug in libssl1.1.1d that may cause the mentioned errors.

Regards
  Christoph