Marc

You can safely ignore that on the standalone requirement checker. That tends to only be used for fresh installs, in which should really be using PHP 8 at this stage

We are aware there are quite a lot of errors that show in the logs at present, and the next version will tone these down. The only ones you need to be aware of at present are ones that show up after upgrade (saying that items will be disabled)

That option is not available on the field type chosen unfortunately. You would need customisation in order to change the locations there

Thank you for bringing this issue to our attention! I can confirm this should be further reviewed and I have logged an internal bug report for our development team to investigate and address as necessary, in a future maintenance release.
 

Check your tables are using INNODB and not MyISAM

Please visit the /admin/upgrade again (replacing with your admin location if needed). You were missing files there

There is actually a key there. That link is specific to the user in which has requested the file. So there is no way in which to get that link without authentication. 
Only a link to it would be returned in any API. It's the application that calls it that would download it. So it your case you would be using WebClient to do this. So something like this (please note, this is outside the scope of support, so any issues would be for yourself to resolve
using (var myWebClient = new WebClient()) { myWebClient.DownloadFile("theURLHere", "destinationFileNameHere.gz"); } With regard the extension, could I please ensure you are using the latest release of the platform? I have seen that issue on the front end which was resolved

This would indeed need doing with a cnames record. (2 in fact). We cannot do this via A record unfortunately. If you would like us to go ahead with this, I can get a ticket created for you in order to get details for your site specifically? 

I see that was sorted for you by my colleague. Please let us know if you have any further issues.

Thats how you would do it if you want to use cross referencing, yes. In all honesty, what you are trying to do isnt really the purpose of cross referencing. I would suggestion just creating that field on each of your databases as a select field unless you do wish for people to be able to click to a state and see a state record

This would indicate that there is an issue with the server config, as mentioned in the message there. Please check folders are still writable, and that you aren't having any issues such as disk space issues in the first instance

That isn't a standard one, no. You can get a standard htaccess from your admin CP by visiting System->Site Promotion->Search Engine Optimisation. You will see "Download this file" on that page

In the first instance, please try using recovery mode to correct this. Its very likely you have items on your site in which are not currently compatible with PHP 8.1
https://invisioncommunity.com/4guides/client-services/getting-support-r292/#recoverymode

If they can do that, they must be set up as a moderator, so would check that first of all. Only moderators can do this

It will only work if you have it set as discussions, as mentioned by my colleague. If you want the email follow ups, then its enable solved, and forum disussions you are looking for

Yes. You would use the word filters for this. If you go to System->Settings->Posting within your admin CP, you will see a word filters tab. You can add words here and choose whether you want to replace, hold for approval, or even block the submission.
 
 

If this is for facebook login, please see the following
 
https://invisioncommunity.com/4guides/members-and-groups/social-sign-in/facebook-r300/
 

Yeah, that would be correct, yes. We do not provide a personalised email service at present

There is indeed. 
For the defaults for members
Go to Members->Member Settings->Notifications and edit the "Followed content" option. 
 
For individuals as a personal preference
Click your name->Account Settings->Notification Settings->Followed Content 

Please bear in mind items will only show if there is something in them to show. This is likely what is causing issues here. For example, you have a clubs block, but do you have any clubs with content? You have a category but is there anything in that category? 
If you can update access details, I can advise further. You need to add your email to log in with, as currently you have displayname, but email is set up on your site

Thank you. I have created a ticket for you on this, and someone will be in contact as soon as possible

Have you checked any other selectors there, to ensure its not simply the selector itself that is incorrect? I ask as from the comment there you appear to be wanting to change a number, where the property you are targeting is a background
I would need to know specifically (please screenshot) what you are trying to change there if you believe this to be the case

There would be no way to reply to a specific post without doing one of the above to state what you are replying to

It can indeed, and that has been done for you

No problem. I will pick up on that now for you