Nokia always tried to provide developers with enough resources so that their app development and testing experience could be great. For this, services such as the Nokia Developer Forum and Remote Device Access (RDA) was provided to app developers. RDA was basically a tool for the app developers to deploy and test their apps on real devices running a live version of the Operating System instead of the emulator which is usually included in the Software Development Kit (SDK). RDA included all popular Nokia devices such as the Lumia(s), Nokia X, Nokia X2, Nokia S40 and Nokia Asha Platform devices.
On August 12th Microsoft took the RDA services down. Although the appropriate SDKs do include emulators which are a good way to test and debug the apps, RDA was an added layer of testing so as to make sure that the apps actually run good on the live hardware as well and not just the emulators. A note left on the RDA webpage read:
Nokia Remote Device Access (RDA) has been ramped down effective 12 August 2014 for all app testing, including Nokia X, Asha, Series 40 and Windows Phone.
We recommend using the Windows Dev Center for the latest on developing universal Windows apps for smartphones and other devices.
For continued support on other platforms, you may use the emulators included in the SDKs:
This isn’t something that was unexpected as since Microsoft took over the Nokia Devices and Services business, they have made a lot of changes such as cutting over 12500 jobs and plans to discontinue most of the Nokia hardware except Lumia devices and their corresponding accessories.
Source – Nokia Developer