Could you please hint me how to query oData properly to determine how soon will I get a tag badge - "Earned 100 upvotes for answers in the [some] tag."
i.e. total sum of all upvotes to my posts grouped by tag, I guess.
There's one query which shows you the amount of badge-eligible upvotes for each tag:
How many upvotes do I have for each tag?. You might want to change