Third availability zone for Heroku Private Space dynos beginning February 2023

Change effective on 27 February 2023

Starting in February 2023, we’re improving Private Space application resilience by spreading app dynos across three availability zones instead of two. This change will improve Private Space app performance and availability. We will begin migrating customers starting this week and will update this changelog once all customers have been upgraded to 3AZs.

If you use the Private Spaces Stable Outbound IP Address feature, you must register all four stable IP addresses in systems that accept inbound traffic from Heroku. No other setup or changes are required with the addition of the new availability zone.

Currently, Heroku publishes four stable outbound IP addresses for each space, but only two are used. With this change to three availability zones, a third address will be used. The only way to determine which addresses are in use is by observing the network traffic to your Private Space.

You can find the stable outbound IPs in the Network tab of your space in the Heroku Dashboard or the CLI:

heroku spaces:info --space example-space