[rahimnathwani]

"If this option is anything like GMail it should be possible to setup the 'send mail as' account as the default to continue sending and receiving mail from the custom domain using ImprovMX's SMTP."

I suspect the no-cost option will be nothing like Gmail. My guess is that they'll allow use to use everything except Gmail.

[NipponBill]

Everyone is still speculating about this, but most have been leaning toward the no-cost option being a Gmail address (https://9to5google.com/2022/01/27/g-suite-legacy-transfer-gm...). The wording on the Google support page mentioning the no-cost option is still vague enough to have me doubting this as well.

If the no-cost option isn't Gmail, then there's the option of obtaining new Gmail accounts and transferring the data to them manually. Then the ImprovMX option should work.