In the migration guide, we're documenting the removed SCSS variables for the line height utilities but not the CSS classes. These should also be added:

List of removed classes:

• .lh-hair
• .lh-line
• .lh-micro
• .lh-mini
• .lh-small-regular
• .lh-regular
• .lh-small-large
• .lh-large
• .lh-big
• .lh-bigger-big
• .lh-small-huge
• .lh-huge
• .lh-small-giant
• .lh-giant
• .lh-bigger-giant