Starting January 13, 2026, Shopify is enforcing stricter Liquid parsing for all themes. This improves code quality, prevents syntax errors, and enables future Liquid enhancements.
What is the recommended route for testing theme code for these issues ahead of enforcement? shopify theme check and the VS Code plugin don’t pick up most of the examples in the migration guide.
Will merchants be notified about exact timing ahead of enforcement?
Minor error in the migration guide page: the “To fix this remove the =>:“ text is repeated from the “Invalid expressions used in case statement” section (an oversight left over from a copy/paste?) in the “Comments must be written on their own line” section.
Thanks for flagging this @jessec - we’ll update the docs asap!
What is the recommended route for testing theme code for these issues ahead of enforcement?
There is no specific route we recommend other than analysing your themes using the the migration guide. You could also use the guide in .md format in your own dev environment with Cursor or similar to analyze your theme project files to find instances where there might be syntax errors.
Will merchants be notified about exact timing ahead of enforcement?
No - this is a background job and merchants will not be notified.
I’m confused how/when this is handled. Based off this X comment by Ben it sounds like it’s not a background job per se, but more a thing that will slowly happen on CLI pushes/zip uploads?
The initial rewrite for existing themes is a background job (where a comment is left), and then after this pushes/saves will be blocked in the same way that other syntax errors are blocked today (comments won’t be left).