The Layla requires that you claim the Layla Commendation to upgrade the unit past level 21. This is available in the store and costs 20 Blood Thorium.
Once you claim this, you can continue upgrading as normal.
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- NEW! In-Game Store Guide
- War Commander 101, Part 1: Introduction/The HUD
- Where is my Blood Thorium?
- Where are my Medals?
- Where are my units?
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