What do the scores in badminton go up to?

Answer 1

The modern scoring system has a nominal winning score of 21, and a point is scored whether the winner was serving or not. (The old system stopped at 15, with only service wins scored.)

However, one side must have a 2 point lead to win, otherwise the tied game continues to a maximum of a 30-29 win.

Answer 2

for the new rules 21 points is needed to change courts