How do EPV effective dates and history work in BAW, and how do I change a value for the future without a redeploy?

Question

Business wants the credit limit used by our process to change on the first of next month, without a deployment. We heard EPVs can do this - how are values scheduled, who can change them, and how do running instances behave?

Answer 1

Exposed Process Values (EPVs) are exactly for this: named values defined in the process app / toolkit, with runtime values that administrators change per environment, each change carrying an effective time. The engine picks the value whose effective time is the latest one in the past at the moment a script reads it.

• Define in Process Designer: EPV "Limits" with variable creditLimit (Decimal, default 5000). Expose the EPV to a team (e.g. "Business admins") - that team may change values in Process Admin (or Process Portal's admin view) without being tw_admins.
• Read in scripts and conditions: tw.epv.Limits.creditLimit - in a BPD gateway condition, a script task, a service, even in a coach (client side the value is the one at coach load).
• Schedule a change: Process Admin > Installed Apps > app > snapshot > Manage EPVs > Limits > Add value: new value 7500, effective 2025-07-01 00:00 - the current value stays 5000 until then; the history shows past, current and future values. Scripted with the Operations REST (BAW 20+):

PUT /ops/std/bpm/containers/CLM/versions/2.3/epvs/Limits   (JSON with the variable, value and effective_time)
{ "variables": [ { "name": "creditLimit", "value": "7500", "effective_time": "2025-07-01T00:00:00Z" } ] }
GET /ops/std/bpm/containers/CLM/versions/2.3/epvs?optional_parts=previous_values,current_values,future_values   -> the full history

Behaviour: running instances are not "on" a value - every read takes the value effective at that time, so an instance that evaluates the gateway on 1 July uses 7500 even if it started in June (design your logic so that this is what you want; freeze a value in a variable at start if the instance must keep it). Values are per installed snapshot and per server; use the sync / copy EPV operations when installing a new snapshot so that the history moves along (question on promotion). Compared with environment variables: EPVs have effective dates, history, business-user editing and can be used in BPD conditions directly; environment variables are technical settings changed by administrators.

References

• BAW documentation - exposed process values
• Operations REST API - EPV resources