Important! Potential security hole, that Facebook decided to force on you almost silently.
I just got a notification, that they will disable 2-factor authentication on devices, that were used frequently for the past 2 years. The notification leads to https://www.facebook.com/settings/?tab=security settings page. I recommend you to opt-out of this feature, which allows to trust frequently used devices.
Firstly, the page shows very obscure devices' names, it is difficult to identify what they are. Secondly, it shows not the date of the *last* activity, but the date of first login (I had some devices with date in 2013!). Thirdly, it's unclear what is meant by "frequently": daily? Monthly? Annually? Fourthly, what data is used to identify the devices? If it relies on User-Agent (which is most likely, may differ only for Facebook's own app) - it can be easily spoofed.
What I mean is, that this "convenience", that they seem to be forcing to let you not use 2FA on trusted devices, can easily become a security hole for your data.
I strongly recommend to opt-out of it using the link above. Considering how their sessions work, chances are you will only use 2FA for the 1st login on your device and never again anyway. But letting Facebook create/update sessions based on some unreliable data is definitely a bad idea.
