diff --git a/docs/libcurl/curl_share_setopt.3 b/docs/libcurl/curl_share_setopt.3
index cbdbdc558e4f2a9402c264d7e621ea72de96fd74..55e06f1290faa3c36f3491a244ca08513acc669f 100644
--- a/docs/libcurl/curl_share_setopt.3
+++ b/docs/libcurl/curl_share_setopt.3
@@ -68,7 +68,8 @@ be used!
 SSL session IDs will be shared across the easy handles using this shared
 object. This will reduce the time spent in the SSL handshake when reconnecting
 to the same server. Note SSL session IDs are reused within the same easy handle
-by default.
+by default. Note this symbol was added in 7.10.3 but was not implemented until
+7.23.0.
 .RE
 .IP CURLSHOPT_UNSHARE
 This option does the opposite of \fICURLSHOPT_SHARE\fP. It specifies that