diff --git a/src/modules/tls/README b/src/modules/tls/README
index 21740840b4c..a8b83eda173 100644
--- a/src/modules/tls/README
+++ b/src/modules/tls/README
@@ -1271,12 +1271,18 @@ modparam("tls", "renegotiation", 1)
 
    Allow setting flags that control how the module is initialized and
    works at runtime. Many flags (bits) can be set at the same time (set
-   the parameter to the sum of corresponding values).
-
-   If flag (bit) 1 is set (value 1), the memory management operations
-   registered for TLS are wapped within a pthread mutex lock. It can be
-   useful with newer versions of libssl and libcrypto, which have a more
-   pthread multi-threading oriented design.
+   the parameter to the sum of corresponding values). The flags are
+   refered with 0-indexing.
+
+   If flag (bit) at index 0 is set (value 1), the memory management
+   operations registered for TLS are wapped within a pthread mutex lock.
+   It can be useful with newer versions of libssl and libcrypto, which
+   have a more pthread multi-threading oriented design.
+
+   If flag (bit) at index 1 is set (value 2), the module executes openssl
+   fork prepare API functions (see
+   https://www.openssl.org/docs/man1.1.1/man3/OPENSSL_fork_prepare.html).
+   It is done only for openssl version greater or equal with 1.1.1.
 
    Default value is 0.