Dropbox ends XP support with only a month's notice
dropbox.com
dropbox.com
XP has awful TLS/SSL support. No SNI (that's what allows you to host more than one domain/certificate on a single IP), ancient ciphers. This sort of encryption stuff is the bread-and-butter of Dropbox's service and having to maintain an in-client replacement to supplant the host's must be exhausting.
That's well before you consider that allowing XP machines to keep puffing along makes the internet a worse place. They get no updates, they're infected, rotting, smouldering sludge heaps just another day away from joining a botnet if they aren't already part of one. Third party software on them is starting to rot too. This all puts the rest of us at risk.
XP is the passive smoke of the computing world. Kicking it off the internet is the best result for everybody.
Edit: That isn't to defend the way Dropbox has done this. Just checked the Wayback machine and their minimum requirements page has been bleating on about supporting XP right up until now. They should have removed it from being officially supported when Microsoft did in 2014.
If you still use XP, you either have to for some legacy piece of software controlling some piece of expensive hardware, where it lives in some sandboxed environment (i.e., no public internet), or you are a government paying Microsoft through the nose for extended support contracts. If you really need Dropbox in that latter case, you can either afford to pay Dropbox an outrageous amount of money for that extended support (I am sure they are more then willing to if the price is right), or you just have to deal with it.
Anyone running XP should by now be aware that things will break down at awkward times and with little warning.
A public deprecation plan would be better next time.
How many people still use XP with Dropbox on an internet connected computer? And how many of those are paying customers? For Dropbox it makes no sense to go with more than what they are doing now. Why spend a lot of money in postponing the inevitable? It won't net them any returns, whilst dropping supported for a legacy OS does have tangible benefits (e.g., reduced build times, less (untestable) code, less support).
If you really need to run software on an unsupported, unpatched OS, you are way out of the realm of of-the-shelf supported software. You need a custom agreement with the vendor to get that level of support, and you would have gotten ample warning on the impending loss of support with such a contract.
It would be different if Dropbox axed support for Windows 8 with only a month of warning, even though they are fully within their rights to do so.
Dropbox has known about the death of XP from 2014. It shouldn't have taken them over two years to remove XP from being a headline supported operating system. They should have said something months ago. They're the service provider. The onus is on them to communicate this stuff in good time.
Notice is important because organisations (of all sizes) have legacy systems that can take years to migrate to newer operating systems. Long notice about when your software dies allows you to plan. 30 days notice is going to ruin August for some people.