There are still numerous popular apps such as WhatsApp and Facebook for example, that don’t provide support for multiple accounts. It certainly makes sense for one person to have multiple accounts in many situations (e.g. work and personal accounts).
If you have a jailbroken iOS device a Cydia tweak called AppDuplicator allows you to download and use duplicates of apps.
The tweak makes it possible to install original apps from the Play Store along with their duplicates and as a result, sign into different accounts.
AppDuplicator supports most social apps and even takes user requests to implement support for more titles. Furthermore, the tweak can send notifications to let you know if new apps have reached their support list.
How to download and use app duplicates with AppDuplicator
Cloning apps with AppDuplicator is very easy. Run Cydia and wait for your sources to refresh. Then add the repo http://apt.imokhles.com/ and install AppDuplicator from there.
Once the tweak is installed, head over to the Settings app and open the tweak’s page. There, you will find all supported apps and install as many duplicates as you want.
The tweak runs well for the most part. The only problem that can happen is duplicated apps crashing but you can fix that by reinstalling them.