I have had one or two problems with upgrades over the years, but I have upgraded as a release comes out. I did have a problem with a access list and zone based firewall, but that was easy to find. CCA 2.2.4 is a lot more sophisticated compared to earlier releases.
Was your configuration produced via 'out of band' CLI configuration, or was the configuration produced by Cisco Configuration Assistant ? Don't know, to many variables to guess if it will work for you.
To play it safer;
check CCA release notes to check caveats.
If you have any customised Music on hold files or customized phone background images or customized list.xml files, back them up as well so they can be restored after the software upgrade.
You will have to take a option during the upgrade to tick an option for a disk cleanup , which will delete the contents of the flash card and restore newer support files. The startup configuration or script for the system is stored not in flash but in Non volatile battery back up RAM, so your running config will be saved.
But just to play it safe, i personally would backup via tftp of both the CME and CUE configurations to my TFTP server, so if i had to back out I could.
I would hope that you had a "Smartnet" maintenance agreement on your UC520, in case you do needed expert Cisco TAC support. You may even like to open a pre-emptive TAC case now and let the technician know that this is what you are doing and get advice from that TAC technician. Keep the case open so that if something does go wrong, you have contact information for a TAC technician who knows what you are trying to achieve. He/She may also, on your behalf, do some background checking to see if there are any caveats that may affect your activity.
You will notice that when you run CCA 2.2.4, can you still manage your current system. If you can use 2.2.4 to add or modify system options, I would think that you should be safe to just give the upgrade a try.
That's my thoughts, others looking at this post may disagree. You always have the option to spend the time, if you feel better about it and upgrade the system release by release..
Let me firstly say, any upgrades you do must have the following done in order to increase the success rate and decrease the failure rate.
Backup your running configuration if this is a production system, even if it is just a lab system but especially if it is production, you can run the following commands to do a backup and then work out the best way to retrieve it.
A: ROUTER# copy start flash:running-config-backup- B: copy this from the flash card onto your PC, I highly recommend using a good compact flash card
Download 3cdaemon and install it, this is a FTP/TFTP program which is free and i have found it to be the most reliable and the most stable to use
After you setup 3cdaemon, browse to your CUE guihttp://10.1.10.1is the default one, or what ever you have made it to be
GO to administration and setup your FTP in the backup section, and then proceed to make a backup of your CUE NOTE:If you are running a really old version of CUE, sometimes when restoring the backup to the most latest version things may not be ported over into this new version, so you must be prepared for this to happen.
The upgrading stage:
It is highly recommended that you use CCA to do this, CCA in its due process will backup the CUE as part of its upgrade procedure, and it does the IOS all at the same time.
Use software pack 8.0.2 I think this is more stable then the previous version, but I do believe it to have some bugs that need to be taken into consideration, what they are exactly I cannot remember of the top of my head
Make sure you let CCA upgrade the phone loads, so when it asks you to choose which phones to install for, make sure you choose only the ones you want, do not waste flash card space.
I would highly recommend you let CCA reset the system back to factory defaults if it is not a production system, then bit by bit copy over the backed up config this way you can make sure that any depreciated configuration commands are not being used any more. If it is a production system and you are onsite and can do the work after hours, again I would highly recommend this path as well, this way you know the system is going to be working at it's optimal performance
NOTE:CCA will create folder/directories on the flash card, please make sure you do not delete these or go placing anything on the root of the flash card, the directory structure will go hand in hand with the configuration that CCA will produce for you, such as your telephony-service phone loads and your tftp-server commands.
Following the above procedure i have successfully upgraded many UC-520's from the very first IOS when they were first introduced to the very latest IOS, but i would be telling porkies if i said they all went smoothly, after all we are talking about Cisco here
nothing ever goes smoothly LOL. You will be fine as long as you have sufficiently prepared yourself, and you are also willing to put some configuration time into the system, if you expect it to all just fit in the spaces correctly, then you are going to be in for a rude shock, for a full CME and CUE upgrade I woudl allocate 3 hours maybe 4 just incase you had to tidy up the config a little more then expected.
A decent txt editor, notepad just does not cut it for me, usehttp://www.brothersoft.com/download-pspad-editor-24977.htmlThis is PSPAD txt editor, it will edit even tcl scripts ;) however it is free and best of all i like it how it lets you compare txt files, I do this to verify configs all the time and this little feature has gotten me out of many of jams :D
That is all i can think of for now, i hope it all goes well for you both and that you only receive very small upgrade pains, even better if none at all.
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