I have years of experience developing both front and back end systems, and am fluent in both English and German. I have strong experience in Java, and with android studio. In addition to this I have vast amounts of other experience in SQL, C,C++, php, unix where even more of my skills can be viewed on my profile and previous jobs. The proposal you describe will be easily be obtained. Changing the theme colour and app name are relatively easy given the source code. I will just simply require the precise colour that you wish to change it to (RGB,hex etc). Modifications can be made to the support page, and I assume by connecting "via socials", external platforms such as facebook are meant. You state that you an apk app which doesn't make it clear whether you have the source code or not. If you do not have the source code, this is fine as it can easily be decompiled back to source code in android studio, depending if there is a ProGuard obfuscation on it. If you do have the source code then it becomes even easier. I am looking forward to potentially working with you.