Apparently, SRAM / Rockshox has decided not to support this shock anymore as they no longer manufacture or stock the air seal kit for it. No distributors seem to have any left in stock, and they will not be able to get them as they've been discontinued. Does anyone have any idea how to get hold of an air seal kit for a Monarch 4.2 HV from 2010?

It seems ridiculous to have to get a new shock since it is impossible to get a standard service part for a recent product.