Updates can sometimes reset your router to factory defaults. Use the Backup & Restore feature in your router's settings to save your current configuration before starting.
TP-Link does an excellent job of retaining legacy support. Unlike some competitors (like Netgear or Linksys) who often bury or remove drivers for older devices, TP-Link maintains a deep archive. You can often find firmware and drivers for routers and adapters that are 10+ years old. tp-link download center