I've updated to

1.0.0-RC1

and now all my actors and channels marked as

obsoleted api

. What apis should we use instead?

You should keep using it until the replacement is ready (after 1.0.0)

is there any way to suppress this warning globally? like gradle flag or something

Yes, the IDE should show help for this with alt/option + enter given you have Kotlin 1.3+ IDE plugin and Kotlin 1.3 in your project (required for kotlinx.coroutines 1.0.0-RC1+ anyway)

it only suppress per method/class. no way to suppress per project. probably i shold create a ticket

There's a way, but it seems the IDE doesn't advertise it. You can create a ticket for this, but you can also search how to opt-in for experimental feature from gradle script/compiler parameter