diff -urN ../exim-4.89.1.orig/src/tls-openssl.c ./src/tls-openssl.c
--- ../exim-4.89.1.orig/src/tls-openssl.c	2017-12-13 00:14:38.000000000 +0200
+++ ./src/tls-openssl.c	2018-02-05 13:35:39.061439000 +0200
@@ -1579,9 +1579,9 @@
 else
   DEBUG(D_tls) debug_printf("no SSL CTX options to set\n");
 
-/* Disable session cache unconditionally */
-
-(void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
+///* Disable session cache unconditionally */
+//
+//(void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
 
 /* Initialize with DH parameters if supplied */
 /* Initialize ECDH temp key parameter selection */