Question: Are the Jazz Masses, like the ones Mary Lou Williams and Joe Masters composed still licit forms of the Mass or have they been officially suppressed at some point in the last 50-60 years?

Answer: 
The 1967 instruction *[Musicam Sacram](https://www.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_instr_19670305_musicam-sacram_en.html)* stated

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> In permitting and using musical instruments, the culture and traditions of individual peoples must be taken into account. However, those instruments which are, by common opinion and use, suitable for secular music only, are to be altogether prohibited from every liturgical celebration and from popular devotions.
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Note that this was written 8 years before *Mary Lou's Mass*, and the same year as Masters' *The Jazz Mass*.

In the 2003 *[Chirograph for the Centenary of the Motu Proprio "Tra le Sollecitudini" On Sacred Music](https://www.vatican.va/content/john-paul-ii/en/letters/2003/documents/hf_jp-ii_let_20031203_musica-sacra.html)* St John Paul II wrote:

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> With regard to compositions of liturgical music, I make my own the "general rule" that St Pius X formulated in these words: "The more closely a composition for church approaches in its movement, inspiration and savour the Gregorian melodic form, the more sacred and liturgical it becomes; and the more out of harmony it is with that supreme model, the less worthy it is of the temple"
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And so in 1903 the rules for church music had been thoroughly formulated by St Pius X in *[Tra Le Sollecitudini](https://adoremus.org/1903/11/tra-le-sollecitudini/)*

Therefore, it seems any "jazz mass" could only take place either outside of a Catholic Mass, or in a Catholic Mass only illicitly.
They are certainly not suppressed, if not less popular than at one point in time. Various churches in the US have weekly Jazz Masses, and multiple dioceses sponsor annual ones (while others have commissioned them for special occasions). There's one coming up next month in Detroit.

This, of course, says nothing on the topic of whether they are licit canonically, but I should doubt that stalwart conservatives like Archbishop Salvatore Cordileone would knowingly celebrate illicit Masses in their cathedral every year. One Jazz Mass you mentioned, from Mary Lou Williams, premiered at St Patrick's Cathedral, if I'm not mistaken.

Certain Vatican music docs from the 1960s (often interpreted as banning certain, usually African-American music forms) are hardly applied even in Rome today, so I suspect they represent a particular historical perspective that has since been superseded by other pronouncements and norms.