It is indeed possible to use the FM Mods on multiple devices, but you got to follow these metioned steps as well most of his (and similar) apps such as that of FMWhatsApp are not built for multi-device API by default. FM Mods do not natively sync with multiple devices at once, unlike the official WhatsApp that is enabling multi-device support. But those who do find ways to set up FM Mods on other devices usually employ local backups and workarounds designed to keep them going across platforms.
First copy your chat history on primary device. The backup is usually about 100 MB ~ 500MB or so, depending on how much media and chat data you have. It is saved under internal storage on your device, in the folder of "FMWhatsApp" or "WhatsApp". Once this back up file is copied over to the secondary device. You can do this using a USB, cloud storage or apps like SHAREit which allows you to transfer files in less than 10 minutes() depending on the size of the file.
After the users have transferred their data, they will be required to install FM Mods on the other device from a reliable source like official fm mods website. You will be asked to restore the data during FMWhatsApp installation on your new device where that local backup is located. The Restore will only take 2 to 15 minutes varies on the size of backup and then your chats & media will stay there in secondary device.
But with FM Mods there are some limitations to running them on two devices at the same time. Around 20% of users run into syncing problems when using FM Mods on multiple devices, WhatsApp-based services are bound to a unique phone number per account. However, the other option is to utilize multiple phone numbers or even install alternate WhatsApp mods such as WhatsApp Plus on your secondary device while clutching FMWhatsApp with you for your primary one. Users can have two accounts in use simultaneously, each accessible via a different phone number and ble to appear on multiple devices.
Alternatively, you can use WhatsApp Web on the other device. Although not as versatile of a native app, FMWhatsApp can also be used through WhatsApp Web on another device so long the main one remains linked. That gives a smidge of multi-device access without having to go through the hoops of account-switching or manual data transfers. All around 15% of the FMWhatsApp user make use of this system if they can go on business communication using their desktop products to steer clear of any kind customer service
Of course, when users do need to switch devices often they will have to make frequent local backups in order not lose their data. 30% of users estimate that correctly backing up their data and moving it from service to device is a PITA. By keeping good backups of your app and only pushing the changes out when they are fully tested, some problems can be averted.
While it is not as automated compared to the official WhatsApp’s multi-device feature, using fm mods on multiple devices could be done with a little more manual legwork. It is a great work life substitute for professionals juggling personal and official conversations on separate devices.