I've just published draft #7 of SRFI 253. It was submitted by Artyom Bologov, author of the SRFI.

Here are Artyom's comments on the draft:

Add check-case

A useful and portability-enhancing one, given that Chicken has a matching primitive and PreScheme is likely to have something like it too. 

Here is the commit summary:

• srfi-253(#rationale): Mention SRFI-143 and SRFI-144.
• srfi-253(#spec–values-checked): Less informal language.
• srfi-253(#prior-art): Rename to #prior for consistency.
• srfi-253(#prior): Not normative.
• srfi-253.html: Fix #prior references.
• impl(check-case): Add generic implementation.
• impl(check-case): Add Chicken implementation.
• srfi-253(#spec–check-case): Add for type dispatching.
• srfi-253.html(#acknowledgements): Update.
• copy edits
• Publish seventh draft.

Here's the diff:

https://github.com/scheme-requests-for-implementation/srfi-253/compare/draft-6..draft-7

Regards,

SRFI Editor