When compiling 5.57 against OpenSSL 1.0.2 I am getting compiler warnings for the cb_new_auth definition. ENGD20 is running V8.4 [840] on ALPHA Building with OpenSSL 1.0.2 Image : STUNNEL.HPE_ALPHA_EXE "session authenticated", cb_new_auth, NULL, NULL); .................................^ %CC-W-PTRMISMATCH, In this statement, the referenced type of the pointer value "cb_new_auth" is "function (pointer to void, pointer to void, pointer to struct crypto_ex_data_st, int, long, pointer to void) returning void", which is not compatible with "function (pointer to void, pointer to void, pointer to struct crypto_ex_data_st, int, long, pointer to void) returning int" . at line number 80 in file DISK$ORACLE:[STUNNEL_BUILDS.stunnel-557.src]ssl.c;1 This appears to be the result of OpenSSL 1.0.2 defining this as an integer function, whilst 1.1.1 defines it as a void function. Duncan