There are essentially two "tiers" of releases from JRiver that you can use, depending on how often you want it to bug you about upgrades.
Tools > Options > Startup > Update Channels:
Latest (may be less stable) - will match the current build posted at the top of this board on Interact. A new build will come out roughly once per week.
Stable - will update far less frequently, but may not include all of the latest changes. This updates when Jim remembers to do it.
Neither are necessarily more or less "stable" (as far as features and operation). Setting it to Stable means that the release will stay "valid" longer (more stable), and Latest means it will bug you once a week or so. To get the latest updates and bugfixes, you can set this to Latest, or come here and download the latest installer from the "sticky release post" at the top of the board.
NOTE: There is also a choice for the Beta builds, which come out almost every day, but you need to be invited to the closed beta group, and be willing to let it crash your computer and mess up your hair.