Suffice it to say here that the upgrade is in approximately one week, so the time to upgrade your node is now. If you run a validator on the beacon chain, you must upgrade before the Altair upgrade epoch or else you will experience downtime penalties.
Note: 4 of the 5 mainnet clients -- Nimbus, Teku, Lighthouse, and Prysm -- have made minor version releases since the original Altair announcement (updated list here). Because these new releases contain a mix of security patches and optimizations, we highly recommend running the latest client release even if you have already upgraded for Altair.