The App Service Environment is v1 and v2 is expiring.
"In August 2021, we announced Azure Cloud Services (classic) will be retiring on 31 August 2024. As App Service Environment version 1 and version 2 run on Azure Cloud Services (classic), we will retire App Service Environment version 1 and version 2 on the same date. Before that date, please migrate to App Service Environment version 3.
App Service Environment is an App Service feature that provides a fully isolated and dedicated environment for securely running App Service apps at high scale. App Service Environment version 3 is easier to use, runs on more powerful infrastructure that can go up to 8 cores and 32 GB RAM with faster scaling speeds for both Windows and Linux, and has much simpler network topology. Here’s a quick comparison between App Service Environment version 1/version 2 to version"
https://azure.microsoft.com/en-us/updates/app-service-environment-v1-and-v2-retirement-announcement/
https://learn.microsoft.com/en-us/azure/app-service/environment/migration-alternatives
If you are using Premium plans, then your not affected. Its only those using ASE (Isolated plans)