First of all I want to say we have installed 3CX V15 for a client pretty much as it was released. The experience was not pretty. There are many differences in some basic functionality that just were not quite ready when version 15 came out and not having some basic features that were available in version 14.5 made the experience a bad one. That being said our install was based on 3CX V15, Siptrunk, Yealink and Cyberdata. All 4 companies are "partners" and are known to play well together. Customer support for all of the myriad of issues we encountered was superb. 1st issue had to do with needing service pack 1 and 2 to be released. Once they were released most Core functions were working. One of the big issues to start had to do with communication to our SIP Trunk and getting audio in both directions. I had a support ticket submitted to both SIPTRUNK.com and to 3CX. SIPTRUNK came through with a work around for our issue and we were able to make calls. 3CX later had a service pack that made the work around no longer needed. 2nd Issue was getting phones to be detected. This was fixed initially with a work around by Yealink, later fixed in another service pack by 3CX. The handsets would be detected but would not properly provision. Yealink had a firmware upgrade and directions to correct. Once the service pack came out it was done automatically. Last big hurdle for us was getting a couple of paging speakers and paging devices working that were put out by Cyberdata. At first they were not even visible by 3CX but after service pack 3 everything was visible and seemingly worked well. I am sure Cyberdata would have helped sooner but we were not trying to get the stuff to work until we had other issues with basic features working for the customer. By the time we were happy and ready to mess with the paging speakers and paging system the service pack was out and all was mostly working. I had one piece of equipment that either went bad or was DOE and Cyberdata sent a replacement right away. I had contacted them late on a Friday and expected to hear from them on Monday morning and instead I received the replacement Monday morning with instructions for returning the other unit. My suggestions to all companies involved is as follows: If you are a company selling or installing 3CX stick with one of their partners for equipment, Personally I will stick with Yealink, Cyberdata and SIPTRUNK. If you are 3CX - test your products a little more prior to releasing a major version so it has at least the same functionality of the earlier version. You can fix new features with service packs but features you have always had should work straight away. If you are a partner/supplier like Yealink, Cyberdata and SIPTRUNK keep doing what you are doing. You saved this customer for us and frankly saved the relationship with 3CX If you are another supported supplier then learn from those three if you need to. So far I have not come across a single 3CX partner that was not excellent. 3CX having a good close partnership with these companies is a great thing. It enables them all to work together to help provide superb service. Last comment for 3CX - you guys did a fantastic job rolling out service patches to correct what I would call an early release mistake. The way you laid out a plan of attack on some of the issues and quickly focused resources to follow that plan so that the service patches would be quick and more important effective was impressive. I might not have been happy with version 15 at the start but now I am very pleased with it.