[asterisk-users] upgrade of asterisk .... to what?

[nik600]

Hi to all

i'm managing a call center with 20 operators using Asterisk.

I'm still using Asterisk 1.2.x as i love his stability.

Now, i'm planning to migrate to 1.4.x, but i don't know what version
to use! 1.4.20 has been released a few days ago, but now there is
1.4.21.

Is there a rule to determine what is beta and what is stable?

Thanks

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nik600
https://sourceforge.net/projects/ccmanager
https://sourceforge.net/projects/reportmaker
https://sourceforge.net/projects/nikstresser