If you have an expired license, HiveManager will lock you to the license page until you enter a valid license. Your APs will continue running as normal unless they encounter a different issue, but you won't be able to manage or update them until you enter a new key in to your HiveManager. The renewal entitles you to hardware replacement should your units fail and technical support should you have an issue.
Aerohive have introduced the HiveManager Connect Platform which is a limited feature version of HiveManager that does not require an entitlement to use, so it is a free to use platform.
Most of the advanced enterprise networking level features are disabled in Connect. To use these features, the HiveManager would need to be upgraded to HiveManager Select by entering an entitlement key; however, this is a one way trip so the HiveManager would not be able to revert back to Connect after an entitlement key has been entered.
Connect does not include hardware replacement or technical as standard, however support subscription pricing is available on request