How many releases to wait before removing the deprecated Compound* elements

[keilw]

In release 2.1.2 of Indriya several references to Compound* were deprecated because the term "Compound" was clearly defined in MeasureUnit.Complexity of Unicode and ICU4J as opposed to "Mixed" (the latter in the sense of "hour, minute" or "foot, inch"), see https://javadoc.io/static/tech.units/indriya/2.1.2/deprecated-list.html

When should we remove the deprecated elements?

[keilw]

1. With the next release 2.1.3

[keilw]

2. With the release after the next, most likely 2.1.4

[keilw]

3. With the next second-digit release, which would be 2.2
   (although this could be reserved for a MR 2 of the JSR and not come so soon after MR 1 in January 2021)