Hello, since we got a few bug reports by now about this issue on GitHub, I thought it might be a good idea to spread the information a little bit: It is a known issue that the 20-test_enc.t test fails in OpenSSL version 1.1.1d if zlib support is enabled (see [1]). Meanwhile, the bug has been fixed on master and the OpenSSL_1_1_1-stable branch (see [2]). The test error can be ignored, if you don't use the `openssl zlib` command, resp. the BIO_f_zlib() filter BIO. However, if you need a fix for it before the next official release, you have two options: - Apply the patch 86ed78676c66 manually to your copy of 1.1.1d (see [3]). - Update to the tip of the OpenSSL_1_1_1-stable branch (see [4]). Regards, Matthias [1] https://github.com/openssl/openssl/issues/9866 [2] https://github.com/openssl/openssl/pull/9877 [3] https://github.com/openssl/openssl/commit/86ed78676c660b553696cc10c682962522dfeb6c [4] https://github.com/openssl/openssl/commits/OpenSSL_1_1_1-stable
