Office 365 Small Business Premium was a great price value for SMBs. As we see the product sunset over the next several months the transition to “New” Business Plans (Business Premium for instance) may create some situations you have not anticipated. The same would also be true of moving to the Enterprise Plans like E3.
In a nutshell the Office Client that is installed with Office 365 Small Business Premium is different than either Office 365 ProPlus or the Office Business offering with is included in Office 365 Business Premium.
The Office Client installation in the New Business plans separates OneDrive for Business and the Lync Basic installation. Notes on the Skype for Business 365 Service description call this out.
The Skype for Business (Lync) client is supported for use with these subscription options, but it is not included. Lync 2013 Basic is available for all customers. The Lync Basic desktop client is a locally installed application that provides presence, instant messaging and conferencing features for Office 365 plans that include Skype for Business Online. Office 365 ProPlus, Office 365 Enterprise E3 and Office 365 Enterprise E4 include the full Skype for Business (Lync) application, which include additional features including advanced telephony support, archiving & compliance features. A Skype for Business Online license must be assigned for each user. For more information on Lync Basic features, see Clients for Skype for Business Online.
A good resource for comparing contrasting the Lync Basic client, which is better than it sounds is located here. A quick glance will note no critical or core capabilities missing. examples of missing capabilities outside PTSN integration include no spell checker, Inking, or OneNote integration.
Another point of differentiation is the lack of the Access product.
I occasionally have partners or customers baulk at these differences and style them as unfair. Please realize we have a continuum of offerings and Office 365 ProPlus and/or Office 365 E3 include these advanced capabilities and all the associated client software as part of the price. That increased price is what differentiates them from lower priced offerings.
When one upgrades, migrates, moves, transitions (you pick) from Office 365 Small Business Premium one must uninstall and then reinstall the Office software. The bits are different and have different capabilities, though most are the same. This process is articulated in a great support article which discusses errors such as "Your subscription has expired" or "Unlicensed product" or "Product deactivated" which occur during this transition. It later provides explicit instructions for reinstallation.
The important thing to note is to let the customer know ahead of time they may see these errors and that the reinstallation will be necessary. Managing the customer through this process takes time and we appreciate your assistance and partnership.
UPDATE: I wanted to also note that a similar experience occurs when transitioning away from the Office 365 Midsized Business offering as well. The support article does not refer to Midsized business, but the same reinstallation is in fact necessary.
For resellers who have customers on these plans I would encourage you to also refer to the updated guidance Moving to the new Office 365 plans for small and midsized businesses on the Office product website.