Here's a short story:

IPA Braille is the modern standard Braille encoding of the International Phonetic Alphabet (IPA), as recognized by the International Council on English Braille. 

A braille version of the IPA was first created by Merrick and Potthoff in 1934, and published in London. It was used in France, Germany, and anglophone countries. However, it was not updated as the IPA evolved, and by 1989 had become obsolete. In 1990 it was officially reissued by BAUK, but in a corrupted form that made it largely unworkable. In 1997 BANA created a completely new system for the United States and Canada. However, it was incompatible with braille IPA elsewhere in the world and in addition proved to be cumbersome and often inadequate. In 2008 Robert Englebretson revised the Merrick and Potthoff notation and by 2011 this had been accepted by BANA. It is largely true to the original in consonants and vowels, though the diacritics were completely reworked, as necessitated by the major revisions in print IPA diacritics since 1934. The diacritics were also made more systematic, and follow rather than precede the base letters. However, it has no general procedure for marking tone, and not all diacritics can be written. 

IPA Braille does not use the conventions of English Braille. It is set off by slash or square brackets, which indicate that the intervening material is IPA rather than national orthography. Thus brackets are required in braille even when not used in print. (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: Does IPA Braille use the conventions of English Braille?
Guess: No

Question: what indicates that the material is IPA?
Guess: It is set off by slash or square brackets

Question: are those brackets required?
Guess: Yes

Question: what year did IPA become obsolete?
Guess: 1989

Question: what is IPA?
Guess: the modern standard Braille encoding of the International Phonetic Alphabet

Question: where was it put into use?
Guess: France

Question: where else?
Guess: Germany

Question: who created it?
Guess: Merrick and Potthoff

Question: where was it first published?
Guess: London

Question: when?
Guess: 1934

Question: who reissued it?
Guess: BAUK

Question: was that version successful?
Guess: No

Question: who created a completely new system?
Guess: BANA

Question: when?
Guess: In 1997

Question: was it compatible withe Braille from other places?
Guess: No

Question: what countries was it for?
Guess: the United States and Canada

Now answer the following question in the same format.

Question: who revised the Merrick and Pothoff version?

Robert Englebretson