Dear Kirby community,
one of the sites I’m working on crashed overnight and I can’t really interpret the debug mode error i am getting…
The local version is running without any errors.
Can anybody help? 
This is the error I’m getting:
Whoops\Exception\ErrorException thrown with message “Unknown: [ext-deprecate]:10403 10413 80125 hash_hmac hash_equals”
Stacktrace:
#1 Whoops\Exception\ErrorException in Unknown:0
#0 Whoops\Run:handleError in [internal]:0
Apparently hash_hmac and hash_equals are PHP extensions that are deprecated on your server or in your PHP version but are required for Kirby to work. 
Do you also get an error with debug off?
Yes…the site is displayed but everything is out of place…
The panel shows an error:
“This page is currently offline due to an unexpected error. We are very sorry for the inconvenience and will fix it as soon as possible.”
What PHP version is used on the server? If this really changed overnight without you doing anything, your hosting provider has probably updated PHP.
And what’s your Kirby version?
I’ve updated on the latest version of Kirby just to see if it makes a difference – but there error is the same. PHP is 8.1 – I’ll check with the provider if they’ve changed anything.
Thanks for all the help and answers so far.
Just got the same error on a client page of mine. The page is running with Kirby 3.6.1 and PHP 8.0.28. As far as I know, nobody changed anything, so it seems most related to an internal update of my clients provider checkdomain.de?
Even with debug mode off, the page renders with layout shifts and shows an error message “This page is currently offline due …” at the bottom.
Currently I have no idea how to fix this problem. I added two screenshots to my post, which showing the current configuration of the domain with checkdomain.de and the debug error message from Kirby.
I’d try to disable the warning error level in php.ini. Unfortunately, I found only 1 or 2 links searching via Google regarding this error message and they were not helpful.
Thanks @texnixe for your quick reply. Sadly I have no access to php.ini. What’s very interesting, that @granadahills is with checkdomain.de as well (if I didn’t misread his error message). So it seems a problem with that specific provider.
I’ll try to contact checkdomain …
Yep, looks like it. I mean, if you don’t update your site and don’t make any other code changes and something happens out of the blue, it’s almost always some change on the hosting side(or a hacker, unlikely in this case).
Hey Jash! Exactly. It’s also checkdomain.de – my client reached out to their support. Guess this might take a moment. Let’s see what happens. I’ll temporarily host the site somewhere else.
Rather relieved to hear it’s a server issue…
Adding a 1+ here, I am having the exact same problem with a Kirby 3.9 install on a checkdomain.de Server! Will get in touch with the support, too.
Just talked to a rather unmotivated support person via phone. He just said that it must be a software issue – however i should send all error logs via email again and they’ll have a look. Let’s see what happens.
I think its not exclusively related to checkdomain.de. Google results slowly increasing to this topic (like https://wordpress.org/support/topic/since-wp-6-4-update-checkout-not-working/).
It seems really something to do with an (auto) update to php servers, which broke something in its error handling.
I have the same problem. As a quick fix for the “everything out of place” frontend I changed the file kirby/views/fatal.php like this:
<?php /* ?>
<?php include __DIR__ . '/snippets/header.php' ?>
<p class="notice">
This page is currently offline due to an unexpected error. We are very sorry for the inconvenience and will fix it as soon as possible.
</p>
<p class="admin-advice">
Advice for developers and administrators:<br>
Enable <a href="https://getkirby.com/docs/reference/system/options/debug">debug mode</a> to get further information about the error.
</p>
<?php include __DIR__ . '/snippets/footer.php' ?>
<?php */ ?>
<!-- This page is currently offline due to an unexpected error. We are very sorry for the inconvenience and will fix it as soon as possible. Advice for developers and administrators: Enable debug mode to get further information about the error. -->
The css in the header.php overwrites your styles.
We see the same issues with our shared webhosting at dogado.de. Several projects at dogado are affected (independent webhosting packages/servers).
So far we received the following feedback from dogado’s support:
"This is not a deprecated function but a monitoring tool that tells us which functions are currently being used that may still need to be made available on a new platform.
It is therefore not an error, but a purely statistical survey that is necessary for migration planning and only remains active for a certain period of time."
Still waiting for their response on how dogado thinks we can solve this.
The issues described above just disappeared on our projects hosted at dogado.
The issue has gone on my project as well.
Same here 
