I've just published draft #5 of SRFI 152.  It was submitted
by John Cowan, author of the SRFI.

  <https://srfi.schemers.org/srfi-152/>

Here are John's comments on the draft:

  This draft incorporates all of Sudarshan S Chawathe's
  corrections.

  The rationale for omitting UTF-32 conversions is that it
  is essentially an unused encoding.  UTF-16 is used for
  Windows APIs and some files; UTF-8 is used essentially
  everywhere else, including the Web (90% of web pages are
  UTF-8).  The only advantage of UTF-32-encoded bytevectors
  is that theyt are both fixed-width and mutable, but on
  Scheme systems that intern characters (which is most of
  them), vectors of characters serve the same purpose with
  greater ease of use.  R7RS and this SRFI already provide
  string->vector and vector->string conversions.

Here's the diff:

  <https://github.com/scheme-requests-for-implementation/srfi-152/compare/bacab885617d341b73a4c893fc027ce0797f608d...5916c1ed18245857dec9ec93bbb8da97bb392705>

Regards,

SRFI Editor