How do edits to a sequence affect existing enrollments?

When you edit a sequence — change a step, update copy, change timing, change routing — those edits don't retroactively affect emails that have already been sent. But what happens to contacts mid-sequence, and what happens to new enrollments, depends on a few rules and one important choice you make when you publish.

The general rule

Edits affect:

• All future enrollments — new contacts entering the sequence after you publish use the new version.

• Existing enrollments going forward — for steps a contact hasn't yet reached, the new version applies.

Edits don't affect:

• Emails that have already been sent — those are out the door, no longer editable.

The publish-time choice: upgrade existing enrollments

When you publish changes to a sequence, the Publish dialog asks whether to upgrade existing compatible enrollments to the new version. Check the box and Unify migrates eligible in-flight enrollments to the new copy.

Two things to know:

• Compatible enrollments are upgraded — most enrollments on the previous version that haven't already passed the affected steps.

• Agentic enrollments (sequences with AI-personalized copy generated through Chat) need to be upgraded through Chat. The Publish dialog will note this. The reason is that the AI-generated copy needs to be regenerated for each contact against the new template.

If you leave the checkbox unchecked, existing enrollments continue on the version they're already on. New enrollments use the new version.

Behavior by edit type

Step copy or template variables

• Future enrollments: use the new copy.

• Existing enrollments not past that step: use the new copy when they reach the step.

• Existing enrollments past that step: unchanged. The version-upgrade option at publish time can move them to the new version where compatible.

Step timing or delays

• Future and existing enrollments use the new delay for steps they haven't reached yet.

• Steps already sent or already scheduled at the old time aren't retimed.

Routing (mailbox or owner)

• Only applies to new enrollments. Contacts already in flight continue sending from their original mailbox.

• To reassign existing enrollments, use Email Backlog → Reassign Sequence Enrollments. See How do the send queue and email backlog work?

Adding, deleting, or reordering steps

• Adding a step at the end: existing enrollments pick it up when they reach the end.

• Adding a step in the middle: existing enrollments don't go back to receive the new step. Future enrollments get it.

• Deleting a step: existing enrollments past that step are unaffected. Enrollments not yet past it skip it.

• Reordering steps: enrollments continue from wherever they are; the order change applies to steps they haven't reached yet.

Resuming a paused sequence

When you resume a paused sequence, queued sends pick up on their original schedule. No backfill of missed sends — the schedule continues from where it was.

When an enrollment gets stuck on "Blocked"

A blocked enrollment usually means a piece of personalization in the email couldn't be filled in for that contact — a custom field is empty, a snippet returns nothing, or a fallback isn't set.

To diagnose, open the enrollment from the Enrollments tab. You'll see which variable is failing. Fix the field on the contact's record (or in your CRM), or update the sequence copy to handle missing values gracefully.

After fixing the underlying data, blocked enrollments progress on the next system check.

One technical limit worth knowing

Once Step 1 has sent, you cannot change which mailbox the rest of a contact's sequence sends from. Unify keeps the sender consistent for the recipient. If you try to reassign a mailbox on a contact who has already received Step 1, the change won't apply for that contact (you'd see this as an error in the Email Backlog reassignment flow).

When to duplicate instead of edit

Edit the existing sequence when:

• The change is incremental.

• You're fine with existing enrollments picking up the change on their next applicable step (or you upgrade them at publish time).

Duplicate the sequence when:

• You want a clean break — different copy, different timing, different audience.

• You don't want existing enrollments to be affected at all.

• You're testing a meaningful variation alongside the original.

For starting individual contacts over from step 1, the path is: unenroll from the existing sequence, then re-enroll in the duplicated sequence (you may need to enable re-enrollment in your sequence ruleset — see How does sequence re-enrollment work?). Re-enrolled contacts start from step 1.

When changes don't seem to be taking effect

A few things to check:

• Did you publish? Edits are saved as draft until you click Publish.

• Did you upgrade enrollments at publish time? If you didn't check the box, existing enrollments stay on their previous version.

• Are you looking at the right step? A change to a step a contact has already passed won't show up in their record. Look at their next upcoming step.

• Is the sequence paused? Paused sequences don't process queued sends.

• Give it time. Most sequence-level settings take 15–30 minutes to fully propagate.