I currently use CCM 3.3(3) running on MCS-7835H-2.4-EVV1 serving about 100 IPPhones. I would like to upgrade it but thruly am not sure to which version. It seems that 4.3 should be enough in regards to required functionalities. However, I am concerned about the future of this release. I wouldn't like to perform additional upgrade in 2 years after 4.3 becomes EOS, or so. What is the advice? Should I upgrade to 5.x or maybe to 6.x? Should I also change hardware?