Upgrade after a long time

Hello,
I didn’t upgrade my ccr1009-7g-1c-pc since a very long time …

The RouterOs version is 6.40.5
The latest is 6.43.8

As I read in the wiki that some parts have been rewritten then I don’t dare upgrade.
First of all I shall backup the configuration and, in case of problems, I could reinstall it. But I am not reassured !

Which advices could you give me ? Please don’t give me references in the wiki.
Thank you in advance,

The big difference between 6.40 and 6.43 is in the way how ethernet ports are handled. If you post here part of your running config (/interface export … I don’t think there are sensitive settings in this section) we can express our opinions about probability for things to break during upgrade…

[admin@MikroTik] > /interface export

jan/20/2019 18:07:12 by RouterOS 6.40.5

software id = CCV8-MISI

model = CCR1009-7G-1C

serial number = 7AF40788DE3D

/interface bridge
add name=bridge1
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
add bridge=bridge1 interface=ether4
add bridge=bridge1 interface=ether5
add bridge=bridge1 interface=ether6
add bridge=bridge1 interface=ether7
/interface bridge settings
set use-ip-firewall=yes
[admin@MikroTik] >

I don’t want to relive this adventure:
http://forum.mikrotik.com/t/my-router-probably-broken/114864/12

I don’t see any reason why upgrade should break things for you. Config is just the way it is supposed to be in most recent ROS versions.