FM Mods like FMWhatsApp adds a lot of customization and new features on top but their security was always being questioned. Though FM Mods are known for their better privacy settings, added features and upgrades over the default WhatsApp app, they have no official recognition or backing from WhatsApp which some could see as a risk. Almost only 20% of the traffic switch to FM Mods as then you can have better access over the privacy but here is where these peeps will get their account suspended by WhatsApp which strictly says on its TOS that modded versions are not allowed.
Citing these examples, security experts worry that FM Mods will ignore such concerns in order to optimize for things like data encryption. This is not the case with all FM Mods, however; some do not offer compulsory end-to-end encryption in agreement to official WhatsApp. A cybersecurity report in 2021 had also highlighted that the alternative version like FMWhatsapp of WhatsApp were susceptible to data leak if downloaded from unverfied sources. The security bug had opened up private conversations to external viewers, threatening the privacy of those making use of Discord as a communications platform.
The possible threat of Malware can be another issue. FM Mods are usually circulated in sources other than the official app store, Google Play making them an easy target for bad actors to bring alterations. Some versions had spyware or malware infecting users' devices, and they did not even know that. Nearly 15% of the users that encountered issues with modded apps, mostly for games and other services like Spotify Premium downloading from untrusted sources.
By contrast, a should really trust the legit provider (FM Mods from fmmods & ModdingWelt) on significantly less Problems. Approximately 85% of users that download the mod from trusted sources are secure in its security. However, it is important to keep the app up to date since many security weaknesses can be introduced into obsolete FM Mods which ends them in access leak and incompatible with new OS versions.
Summary fm mods are great for power users who want to modify absolutely everything and be as private as possible, but without official support and unpatched security holes one must weigh the pros with cons carefully. There are, however, some very good reasons you would want to install them but users have the choice of whether they think these mods outweigh any potential risks associated with downloading third party apps from outside official channels.