Analyst house Forrester has identified five key issues that IT buyers need to consider before purchasing Microsoft products and upgrades after the company's recent pricing and licensing changes.

Although most of the changes were in favour of the customer, Forrester said that Microsoft has not done enough to address concerns such as the complexity of licensing for desktop virtualisation, and the mismatch between the cost and value of Office upgrades.

Read Forrester analysis exclusive to CIO UK

For example, the analysts warned that the price of Office Pro Plus 2010 had increased compared with Office 2007 from 1 May. Those with active Software Assurance before this date had instant rights to the new version, as well as access to extra modules that new buyers did not have.

Forrester said that this highlighted the fact that Software Assurance on Office is too expensive for many customers -- yet it could mean they miss out on new upgrade rights if they do not have it. It therefore recommended buyers to thoroughly evaluate the possible benefits of Software Assurance before committing to it.

Another issue that Forrester draws attention to is Microsoft's clarification on licensing options for virtualised and mobile office deployments.

From 1 July 2010, the primary user of a PC with an Office licence has rights to Office Web Apps with Office 2010, and get office roaming use rights (RUR) with active Software Assurance (SA). This means that the primary user can access Office Web Apps from PCs and external devices, and has rights to access Office via any streaming or virtualisation technology.

Forrester said that this clarification means that buyers may decide to retain SA on selected Office licenses in order to get the roaming use rights, but advised: "Ask your operations colleagues to evaluate alternatives that don't involve buying additional licenses or SA, including using the licensed PC as a server using solutions like GoToMyPC, pc Anywhere, or Office Web Apps. These options may be sufficiently credible to provide some negotiation leverage."

In addition to this, Microsoft has made changes to the Windows licensing policies regarding its use in virtualisation cases by extending device roaming rights and offering two ways to license virtual desktops.

From 1 July, customers with SA on their Windows client operating system will be able to access their Windows OS in a virtual desktop infrastructure environment without a separate subscription. Furthermore, PCs without SA on Windows will have access to a new licence called Windows Virtual Desktop Access.

Although Forrester said that these changes were "for the better", it was worried about SA playing such a large part in desktop virtualisation plans.

"Decisions concerning SA and Windows are no longer about just upgrade rights and other SA benefits. Sourcing managers must work with those responsible for their desktop environment to understand their desktop virtualisation plans and factor them into their Windows licensing strategy," it said.

Other issues Forrester identified include the replacement of the Select Licence program and the loss of a grace period for Software Assurance.

Microsoft announcing that it will replace its Select Licence with Select Plus from 1 July, Forrester encourages customers to upgrade to the Select Plus program as soon as possible. On the launch of Select Plus in 2008, Forrester had said that it believed the newer program to be "an improvement" on its predecessor.

Meanwhile, it warned that buyers will need to plan ahead before the expiry of Software Assurance, as Microsoft has removed a 30-day grace period in which a customer can renew Software Assurance without a penalty. This period used to be available when Software Assurance expired at the end of a Select License Agreement, and was useful for some customers to negotiate their terms for a new agreement.