> From: openssl-users [mailto:openssl-users-bounces@xxxxxxxxxxx] On Behalf Of Venkata Ramaraju Vana via openssl-users > Sent: Wednesday, February 05, 2020 00:40 > Error 300 error C3646: 'DEPRECATEDIN_1_1_0' : unknown override specifier xxxxxx\thirdparty\openssl\include\openssl\bio.h 689 1 xxxxx You seem to be failing to include the opensslconf.h that was created as part of the build process (before including bio.h, etc). opensslconf.h is included by many of the OpenSSL headers, but not bio.h. So either you need an explicit #include <openssl/opensslconf.h> before including any other OpenSSL headers; or you have one, but you're picking up the wrong opensslconf.h. (The latter is an easy mistake to make, as not everyone realizes opensslconf.h is a generated file and applications must include the one corresponding to the precise build they're using.) -- Michael Wojcik Distinguished Engineer, Micro Focus