Today, we announced the Kiln merge testnet: https://blog.ethereum.org/2022/03/14/kiln-merge-testnet/
The network, currently running under proof-of-work with a separate beacon chain, like the Ethereum mainnet, is expected to fully transition to proof-of-stake mid-week. We encourage everyone to use Kiln and make sure your application/service/tool/staking setup works as expected in a post-merge context.
Here are some resources to get started on Kiln (see the post for more):
If there are issues in any of your workflows, now is the time to report and fix them.