mise à jour android v2.3.6 à v4.x.x ou pas ?

Should I update my Samsung android (firmware?) from original v2.3.6 to v4.x.x ?

- I am a 69 year old dinosaur



I have a ...



Samsung Galaxy S2 4G phone (GT-19210T)

- (T= Telstra compatible, our Australian carrier, unlocked)

Android:= 2.3.6.



The phone is only used for phone calls and SMS (no internet).



I found this ...

[Update Android 2.3, 2.3.x etc To 4.0,4.1, 4.1.1, 4.1.2, 4.2.2, 4.3, 4.4]

at ... updateandroid.weebly.com

... but it looks a bit suspicious to me, nor do I know if I should leave the phone alone or update the OS/firmware ?



I am having trouble connecting my phone to my PC.

- PC-KiesAir shows an alert Certificate has been revoked.

- so I have decided to clean-reinstall KiesAir on the PC but there is KiesAir and KiesAir3 ... downloads.



Android version dictates which KiesAir version to install on my PC.

KiesAir on PC fell apart after a Kies advice to update.



My biggest fear is ...I screw the phone into a paperweight.



If I should update the firmware/os ...

Q1: where should I get it from ?



Would appreciate any help

Thank you :)