Okay, so, SimplyPlural is shutting down. This sucks, and it's a loss of a disability aid that hundreds of thousands of systems relied on. What now? Here's our personal suggestions:
Update/Edit: After looking into it more and reading their official statement, we've come to the conclusion that we regarded Octocon with a disproportionate level of suspicion, and very hastily, given the chaos of everything that was happening. Whether or not you consider this app to be safe or fit for your needs is up to you and the rest of your system, though we don't currently see a reason to regard it as unsafe.
Lighthouse has also been discontinued, unfortunately, so this is no longer a viable replacement.
With Ampersand going on hiatus, I wouldn't rely on that platform to keep your data stored. Its official blog has been abruptly deleted, so who's to say the app won't abruptly go down too? Granted, it's at least still up for the time being, so it might not be a terrible alternative. Only time will tell where that's going.
The Concordia Project is very promising, but as far as we're aware, there is not currently a usable app available. PluralKit and Tupperbox can also be used for these purposes, and private Discord servers can also be used to log information.
Pronouns.cc is a very good alternative, we think. It can be a little clunky to use for larger systems, but it can at least help with keeping track of basic information.
You can try using Pinterest? You can name boards after headmates and save images to the board that they enjoy or associate with themselves. You can even find flags on there, and you can make subboards for things like clothes they enjoy. We don't personally find this intuitive for our own needs, but maybe someone else will?
I've also heard of systems using excel or other spreadsheets to keep track of system information, which might be more accessible for larger collectives.
Additionally, keep important information noted down in a physical journal. I understand this is not very accessible for larger systems, but this may unfortunately be the only way to ensure that your system information is 100% secure from being suddenly deleted. Information I would consider crucial is name, pronouns, identity labels, roles (if applicable), and formation date (this may be different for other systems, and that's okay! Write down whatever you feel is crucial). For RAMCOA survivors, noting down programming/triggers is extremely important too. For those who don't find manually writing everything accessible, you can print out the pages after typing them out. You can even try to print screenshots of currently existing profiles, if that's something that will save you time.
Seeing as some systems are not in a safe environment to keep a physical journal of these things, I would highly suggest using Ellipsus instead. For those of you exclusively on a phone, you can even try to get creative with world building/character logging apps. I just wouldn't suggest Google Docs, Google in general is not a very trustworthy company.
I know it all looks really really bleak right now, but things will get better. The plural community will find a way to get resourceful and get through this! :)