Microsoft has largely invalidated one of Windows 10's signature concessions to corporate customers, said Gartner analysts who recommended that enterprises reconsider running the operating system's most stable and static edition.
"Microsoft has clarified support plans for LTSB, highlighting restrictions and caveats that could make this an unviable strategy," wrote Stephen Kleynhans and Michael Silver in a Gartner research note to clients earlier this month.
LTSB, or "Long-Term Servicing Branch," is one of three release tracks that enterprises can select for their Windows 10 devices. Unlike the others -- called "Current Branch" (CB) and "Current Branch for Business" (CBB) -- LTSB does not involve once- or twice-yearly upgrades that add new features and morph the user interface (UI). Instead, LTSB versions receive security updates only.
Microsoft conceded the need for LTSB because of corporate customer resistance to the accelerated tempo of added features, changed code and altered UI in Windows 10.
For their part, enterprises saw LTSB as being like decades of past Windows' editions -- including Windows 7 -- in how the new operating system would be serviced by Microsoft, and thus maintained by their IT departments.
While Microsoft cautioned from the beginning that companies should not select LTSB for any but a small fraction of their PCs, both enterprises and analysts thought LTSB would be broadly adopted.
"Some enterprises will undoubtedly try to fall back to the LTSB because it will seem safe and familiar," Kleynhans said in a June 2015 interview.
The promise of LTSB was certainly alluring: Microsoft said it would support each LTSB edition for a full decade, just as it had earlier versions, Windows 7 among them, and thus require corporate customers to upgrade just once during those years.
But as Kleynhans and Silver pointed out, Microsoft's rules revolving around LTSB have changed, making the track less attractive.
The most far-reaching change was quietly revealed as the 22nd item in a long FAQ on Windows support. "Windows 10 Long Term Servicing Branches, also known as LTSBs, will support the currently released silicon at the time of release of the LTSB," the new policy stated [emphasis added].
"As future silicon generations are released, support will be created through future Windows 10 LTSB releases that customers can deploy for those systems."
The tying of support to the latest silicon -- to the current generation of processors and associated chipsets from the likes of Intel and AMD -- was broadly communicated by Microsoft in January 2016, and revised in March.
However, most of the attention paid to the unprecedented change was about how it affected those running Windows 7 or Windows 8.1 on newer PCs. Even though Microsoft also said at the time that "all future silicon releases will require the latest release of Windows 10," there was no clear call-out that the same rule applied to LTSB.
But it did, and does. And there's the rub.
"Many I&O [Infrastructure & Operations] leaders expected to pick a single LTSB release that they would deploy and run for up to 10 years on all their organizations' PCs, old and new," Kleynhans and Silver said in their report. "With Microsoft's latest guidance on LTSB, this is not possible."
The problem, they explained, is that in the face of essentially annual silicon upgrades by Intel, enterprises would have to ditch the idea of sticking with a single LTSB build for, say, five years.
Instead, they could be required to adopt virtually every LTSB version as they buy new PCs powered by new generations of silicon.
"Hardware incompatibility and limitations on support could actually make managing LTSB more challenging than a mainstream CBB deployment," the analysts said.
One solution, though hardly practical, would be for enterprises to freeze their hardware specifications, and try to buy new systems equipped with old silicon.
Kleynhans and Silver dismissed that as "challenging" because as new Intel and AMD processors are introduced, the old quickly vanish from sellers' inventories.
Other options they offered included running change-sensitive applications through a server-based container such as Microsoft RDS or Citrix XenApp from a non-LTSB edition of Windows 10, or pushing Microsoft to rethink the silicon-LTSB rules.
Bottom line, however, is that LTSB is far less attractive than originally presented by Microsoft or envisioned by customers. "For most enterprises, the best solution is to avoid LTSB for broad user deployments and use the more broadly supported CBB," said Kleynhans and Silver.
Because of the support changes, Gartner has slashed its LTSB popularity forecast from an earlier 10% or less by 2020 -- the date of Windows 7's retirement -- to less than 5% by that year.
Yet LTSB is not a completely dead branch, Kleynhans countered in a Thursday interview. "There are still some really important places where you'll want to use it," he said, citing examples such as power plant control systems and devices powering retail check-out machines.