Thanks for posting.
No need to worry as the Server SSL update will not lock out the non-updated clients. The SSL updates were created in response to the issue of new installations of FileMaker Pro unable to see hosted FileMaker Server databases due to invalid SSL certificate end dates (SSL needs to be configured for FileMaker Server to experience this issue).
Older installations were still able to see the databases without any issue and this continued to be the case pre/post Server SSL update.
This Server SSL update also included a fix for Mac 10.5 and Java 6 users who were unable to launch the Admin Console.
Here is the link to the downloads page for anyone who has not updated and needs to:
I always recommend to customers that they upgrade to the latest version of FileMaker, but if everything is working now where your FileMaker Pro clients can see the hosted databases then you should be ok.