Regarding the activation code, it's essential to note that Avast typically provides a 1-year or 2-year license, depending on the subscription plan. Extending the license until 2050 would require a highly unusual and customized agreement, which is unlikely to be offered by Avast.
Avast Premium Security uses a license file to verify the activation status. The license file is usually tied to your Avast account and can be managed through the Avast user interface.