Using third-party applications like Instagram Pro APK may not be legal, as it typically violates the terms of service of Instagram. Instagram’s terms of service generally prohibit the use of unofficial third-party applications to access their platform. Moreover, downloading and installing apps from unofficial sources can pose security risks to your device, as these apps may not undergo the same level of scrutiny and security checks as those available on official app stores. It’s always recommended to use official and legitimate versions of applications from authorized app stores to ensure the security of your device and compliance with terms of service. If you have any specific concerns or questions about using a particular application, it’s advisable to check with the official sources or contact the app’s support for clarification.