I used the basic version (called deluxe) in the previous years, my tax situation did not change, but for 2021 I am forced to upgrade to premier. I noticed that some forms that were supported in the previous years by the basic version are not supported for 2021. Thinking of using another tax sw for 2021.
There is no "Basic" version of TurboTax Online. It only exists in the TurboTax CD/Download edition of the software. In previous years you may have used the Standard version of TurboTax Online. Standard has been replaced with Deluxe which cannot be used if you have things like capital gains/losses, dividends & foreign income on your return. These things are only available in TurboTax Premier Online (or higher) in 2021.
Please see this TurboTax FAQ for more information: Why did I have to upgrade my TurboTax Online edition?