I received a notice from the IRS that they are holding my 2024 refund until I can file my 2019 return. Where can I get 2019 Turbo Tax Software to file for that year?

On the IRS notice you received should be telephone number.  Call the number and speak with an agent to determine exactly why they need a tax return from 5 years ago.

TurboTax does not support tax year 2019