Hi Krzystof,
It is hard to say what version to upgrade to depending on what "feature set" you are looking for. CCM 4.3 has not been announced for EoS/EoL yet so the dates will be a ways down the road. Here are the CCM 4.2 EoS/EoL to work from (so 4.3 will be somewhat later);
End-of-Life Milestones and Dates for the Cisco Unified CallManager Version 4.2
End-of-Sale Date
The last date to order the product through Cisco point-of-sale mechanisms. The product is no longer for sale after this date.
May 15, 2008
Last Ship Date:
App. SW
The last-possible ship date that can be requested of Cisco and/or its contract manufacturers. Actual ship date is dependent on lead time.
August 13, 2008
End of SW Maintenance Releases Date:
App. SW
The last date that Cisco Engineering may release any final software maintenance releases or bug fixes. After this date, Cisco Engineering will no longer develop, repair, maintain, or test the product software.
May 15, 2009
End of New Service Attachment Date:
App. SW
For equipment and software that is not covered by a service-and-support contract, this is the last date to order a new service-and-support contract or add the equipment and/or software to an existing service-and-support contract.
May 15, 2009
End of Service Contract Renewal Date:
App. SW
The last date to extend or renew a service contract for the product.
August 11, 2010
Last Date of Support:
App. SW
The last date to receive service and support for the product. After this date, all support services for the product are unavailable, and the product becomes obsolete.
May 15, 2011
End-of-Life and End-of-Sale Notices
http://www.cisco.com/en/US/products/sw/voicesw/ps556/prod_eol_notices_list.html
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For the CCM 5.x vs 6.x debate my vote would be to go straight to 6.x due to the features and stability.
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You will want to upgrade your Hardware as well as your model is EoL in March 2009 :(
EoS/EoL Annoucement for the Cisco MCS 7835H-2400
End-of-life announcement date
The date the document that announces the end of sale and end of life of a product is distributed to the general public.
December 16, 2003
End-of-sale date
The last date to order the product through Cisco point-of-sale mechanisms. The product is no longer for sale after this date.
March 16, 2004
Last shipment date
The last-possible ship date that can be requested of Cisco and/or its contract manufacturers. Actual ship date is dependent on lead-time.
June 16, 2004
End of software maintenance releases date
The last date that Cisco Engineering may release any final software maintenance releases or bug fixes. After this date, Cisco Engineering will no longer develop, repair, maintain, or test the product software.
March 16, 2005
[Required Milestone for Hardware] End of Routine failure analysis date
The last possible date a routine failure analysis may be performed to determine the cause of product failure or defect.
March 16, 2005
End of new service attachment date
For equipment and software that is not covered by a service-and-support contract, this is the last date to order a new service-and-support contract or add the equipment and/or software to an existing service-and-support contract.
March 16, 2005
End of service contract renewal date
The last date to extend or renew a service contract for the product. The extension or renewal period cannot extend beyond the last date of support.
December 16, 2008
Last date of support
The last date to receive service and support for the product. After this date, all support services for the product are unavailable, and the product becomes obsolete.
March 16, 2009
http://www.cisco.com/en/US/prod/collateral/voicesw/ps6790/ps5748/ps378/prod_end-of-life_notice0900aecd800d8131.html
Hope this helps!
Rob
