Notebarn, my Windows Mobile / Exchange sync notes app, definitely looks like an archaeological relic these days. Dating from early ‘07, before the iPhone era, and being a simple text utility, it is almost comic how it doesn’t resemble modern mobile apps.
That said, I still use it, and it turns out a lot of other people have been using it too. So when a user helped me reproduce a tricky timing bug that could cause data loss under certain circumstances on app initialization, I hopped back into the old (and quite small) codebase to fix it.
There is a little more info on the notebarn project page. Or if you just want to install the app you can install it over-the-air from here. If you already have the app it will automatically install in-place over your existing version. And since the “notes” are actually stored in an Outlook/Exchange Task, the install won’t affect existing data.
A word about backups: notebarn doesn’t have its own data backup mechanism. There are two main approaches to backing up and recovering data if you should lose it for any reason (e.g. problem with notebarn, problem with ActiveSync, accidentally deleting a note you needed, etc.)
One is to lean on whatever backup solution protects all of your Outlook/Exchange data, since notebarn data is really Outlook data. If you can go back to a backup snapshot of this data, even temporarily, you can simply grab the notes data from there. If that’s not practical, you can either manually or via a script back up the “My Notes” item from Outlook tasks, into another place in Outlook, the filesystem, etc.