SHould be fine on CentOS 7. Get the cyrus-imapd SRC RPM or build from source. You need to patch imclient.c since TLS version is hardcoded in.
--- lib/imclient.c.orig 2012-12-01 13:57:54.000000000 -0600
+++ lib/imclient.c 2019-10-03 14:40:11.254566297 -0500
@@ -1695,7 +1695,7 @@
return -1;
}
- imclient->tls_ctx = SSL_CTX_new(TLSv1_client_method());
+ imclient->tls_ctx = SSL_CTX_new(TLSv1_2_client_method());
if (imclient->tls_ctx == NULL) {
return -1;
};
tls_cipher_list: kEECDH:+kEECDH+SHA:kEDH:+kEDH+SHA:+kEDH+CAMELLIA:kECDH:+kECDH+SHA:kRSA:+kRSA+SHA:+kRSA+CAMELLIA:!aNULL:!eNULL:!SSLv2:!RC4:!MD5:!DES:!EXP:!SEED:!IDEA:!3DES:!SSLv3
