Apple has changed its appreciation credit from $200 to $500 for developers in exchange for sending back the Developer Transition Kit (DTK) that was lent to them.

The Developer Transition Kit was sent to Apple Developer Program participants as a lease to make their apps compatible with Apple Silicon. In a recent email, Apple has been asking for developers to send it back and offered $200 in Apple credits.
Apple mentioned in the email how the company ‘heard’ developer feedback and changed the amount to $500 credit, which may be redeemed by the end of 2021.
The DTK was leased for $500 and allowed access to tools and beta software to build Universal apps, private forums, developer labs, resources and tech support. The return credit of $500 may be used to purchase a new M1 Mac or any Apple product. After the initial announcement of $200 credit developers posted their concerns that it wasn’t even enough to buy an M1 Mac mini.