For low range /mid range phone users. memory storage is a very important aspect of the day to day usuage For pros who understand what rooting,linkormove2sd and ext partitions on sdcard can do memory management is far more easier for them.

However, considering the fact that most apps especially social media apps are always on the internal storage of phones (except on a few devices where they are moveable ) over time they accumulate cache,data and update increment that affect storage on the phone .
Facebook app and messenger are the worst culprits of this memory decimation. imagine helping my guy sort out issues with lag on his infinix note 3 and I found out that both apps had a combined memory consumption of 3.4gb jesu. having experienced despite using a custom Rom with all neccesary tools for memory management messenger still refused to respect it's self. I had to put on my thinking cap as I wanted an app that would let me chat with my fb contact while guzzling lower accumulated memory, while giving Me on the go notification and real time access, here I found Disa.

Disa is an app that lets you unify all your instant messaging tools in one place. Users just have to install the necessary plugins from the
Disa interface in order to start using the app.
At the moment, Disa only supports Facebook and SMS, although the list grows with each new update. In any case and even with this reduced list, Disa leaves you with a good impression thanks to its excellent functionality. Another plus for Disa is the huge quantity of options if offers. Regarding notifications, for example, users can choose between the vibrate, sound, or single-color LED options. It allows users to assign Facebook notifications a blue LED light and SMS notifications a green LED light, for example.

pros: (a)low memory consumption
(b) dual functionality (you can Facebook chat and also chat on your whatsapp in the same app.
(c) prompt notification
(d) simple customizable interface
(e) no connection issues
(f) media capable
cons: (a) absence of video calls and online calls
(b) absence of smileys,gifs etc (you can upload via you media storage)
(c) almost all media are uploaded via your phone.
(d) notifications are made for each message received even if it the message iis first in a chat .

conclusion: disa is a life saving alternative to Facebook messenger although I do miss it a lot, I have to stick to disa while waiting for new updates which hopefully would Bring more functionality. I recommend it to those with low and lowering memory on their devices.
cannonleo

you can download it here
http://disa.en.uptodown.com/android or via google play store