This app was first launched on 1st November 2014 and currently has more than 1000000 downloads, a 4.1 stars rating from 24702 users and the latest APK (version 6.6.0) was from 13th February 2020 and is newer than the below reviewed version of the app.
We found these ways of contacting the developers:
The following Analysis is not a full code review! We plan to make code reviews available in the future but even then it will never be a stamp of approval but rather a list of incidents and bad coding practice. We cannot find and tell you all the dark secrets the wallet providers might have.
Do your own research!
Try out searching for "lost bitcoins", "stole my money" or "scammers" together with the wallet's name, even if you think the wallet is generally trustworthy. For all the bigger wallets you will find accusations. Make sure you understand why they were made and if you are comfortable with the provider's reaction.
Luno: Buy Bitcoin, Ethereum and Cryptocurrency advertises on the Playstore:
Keeping your crypto safe
The majority of customer Bitcoin funds are kept in what we call “deep freeze” storage. These are multi-signature wallets, with private keys stored in different bank vaults. No single person ever has access to more than one key. We maintain a multi-signature hot wallet to facilitate instant Bitcoin withdrawals.
This tells us we are dealing with a custodial wallet here. The security cannot be verified.
Not verifiable: No Open Source Code found
This verdict means that we could not find any source to compile the app from. Internally the company might do everything right but as we can't verify it, there is nothing protecting the user from an exit-scam where the provider releases an app that leaks the keys to the servers.
The app cannot be independently verified. If the provider puts your funds at risk on purpose or by accident, you will probably not know about the issue before people start losing money. If the provider is more criminally inclined he might have collected all the backups of all the wallets, ready to be emptied at the press of a button. The app might have a formidable track record but out of distress or change in management turns out to be evil from some point on, with nobody outside ever knowing before it is too late.