Can I run two LMSs in parallel during migration?

Yes — and it's the safest way to switch. Rather than a risky overnight cut-over, you overlap the two systems for a short window:

• Set the old LMS to read-only — no new enrolments, but past records stay accessible.
• Launch the new LMS for active training — new courses, new joiners, and live assignments start here.
• Let in-progress learners finish on whichever system makes sense, then move them.
• Keep the overlap short — two to four weeks is usually enough; a long overlap confuses people about where to log in.

The only cost is paying for both briefly, which is minor compared to losing data or disrupting learners. Once everyone is active in the new system and historical records are exported, retire the old one. Communicate one clear "from this date, use the new system" message so there's no ambiguity.