Locked guidelines export to UFO using invalid syntax

Locked guidelines are not in the UFO3 specification, and when the file is exported to UFO3 it breaks many UFO authoring and production tools. The offending code is <key>locked</key><true/>. When unlocking the guides, exports work fine again.

What version of Glyphs do you have? This should be fixed since the end of last year.

Yep, turns out I was working with files from old versions. Have asked to upgrade.