Files can be pinned in SOS Collab just as in SourceSafe. A file that has been
pinned is denoted with a 
pin symbol. When you pin a file, you are locking in a particular version of
the file. In other words, no changes can be made to a file as long as it is
pinned. Thus, when a Get Latest operation is performed
on a pinned file, the pinned version is the version that will be retrieved even
if there is a more recent version.
Pinning a File
To pin a version of a file, you must look at the revision history of a file.
First, select the file in the File List. Then, click Show
History or choose the Show History command from either the Tools menu
or by right-clicking. Select the version you want to pin from the History
dialog and click Pin. You have now locked this particular version of the file.
A pin symbol will be
displayed to the left of that file version in the History dialog as well as
to the left of that file in the File List indicating the pinned status of
the file.
(Please Note: While you are presented with the option to Edit a pinned file, just as in SourceSafe, you cannot perform this function. An "Operation Failed" error message will appear in the SOS Collab Status Window.)
Unpinning a File
When you pin a file, you typically are not planning to change the file so that a particular version of the file becomes the version that is part of your project. No changes can be made to that file until someone unpins that file.
To unpin a file, select the file in the File List. Click Show History or
choose the Show History command from either
the Tools menu or by right-clicking. Select the pinned version from the History
dialog and click Unpin. You have now unlocked this particular version of the
file. The pin symbol
will be removed from that file version in the History dialog and from the
left of that file in the File List.