There are some errors and a lack of precision in the language of that newsletter, but I would say MMS1 and MMS Classic are the same thing, just different terms for the same thing. Second paragraph in the newsletter has this quote, "He was self-treating himself with MMS classic, (MMS1), after a good friend of his sent him MMS."
The newsletter is from Mark Grenon, not Jim. When they say "MMS1 or MMS Classic" they are not signifying two different things but only two different terms for the same substance.
I think "MMS Classic" is used to distinguish it from MMS2 or CDS or MMS with Baking soda, if Mark uses MMS with baking soda, and I don't know if he does.
Michael