Flow version activation and interview continuity
Key Takeaway
A flow interview, which is one running instance of a flow, continues on the version it started with. Only new runs pick up a newly activated version.
A flow can have many saved versions, but only one version is active at a time. Because interviews that are already in progress continue on their version, admins can change a flow without breaking those interviews.
Flow versions and flow interviews
Each time a user runs a flow through a link, button, or tab, they run a single interview of that flow.
A single flow can have up to 50 versions. When you activate a new version, Salesforce automatically deactivates the version that was active before, if one exists, so you never have to deactivate the old version yourself.