I encountered some dangers that one can run into when upgrading the BizTalk SFTP adapter that can be found on Codeplex.
On one installation where the adapter is used did the issue of the adapter stop working frequently arise. When the issue was fixed in a subsequent version of the adapter, it was upgraded, but the problem remained.
When I looked at the server, I noticed that the adapter never had got upgraded, even though they very well installed the new version. I then replicated what I believe to be the steps taken during the upgrade in order to fully understand what had happened.
I learned that when upgrading version 1.3.3 to 1.4.0, it is necessary to completely uninstall the previous version before installing the new. This was never done during the upgrade process. The old version remained installed and the setup program for the new version reported back that the installation was successful. The BizTalk administrator never noticed the dual entries in the Add/Remove programs window nor the old timestamps in the adapter installation folder (which was how I noticed it from the beginning).
Uninstalling the two adapter entries in the control panel and then reinstalling the new version solved the issue as can be seen in the installation directory.
I then also noticed that when properly upgrading the adapter, receive locations bound to the SFTP adapter will not start unless you for each and every one open the adapter properties windows and save it. This is due to a difference in the properties that will make the bindings fail otherwise, rendering the port to shut down.