I see that Mautic 4 requires a min version of 7.4. This really sucks. Not everyone has the resources to ensure that all code bases they manage are running on latest versions of php (yes I know php8 is after this, but you know what I mean).
Is there any way it can run on 7.3, or will we be staying on 3.3* for some time then?
I guess no one else cares?
Did you actually look at PHP: Supported Versions ?
PHP 7.4 has active support until 28 Nov 2021 so it would be even better to support 8.0 as min version.
I always try to run the newest version of anything if I can. It will mean less work in the future with upgrading. You will have to upgrade to PHP 8.0 sooner or later.
Now that Mautic does not support 8.0 yet I will have to install 7.4 and then in the future upgrade. Would rather have 8.0 from the start of Mautic 4.0.
Lower version means more bugs, more security issues, less performance, less features…
Just stay on older version of Mautic if you want to use old version of PHP…
Not so easy mate when you have dozens of code bases to manage. M4 will exclude a lot of users I think. It’s a real shame.
As mentioned above, 7.3 is already out of active support, and in December will be end of life.
Given we have multiple dependencies which needed to be bumped up to support PHP8 requiring 7.4 as a minimum, and several of which are backwards compatibility breaking changes (so had to be released only in a major release), there was no alternative but to drop 7.3 support.
Unless of course you want us to not release support for 8.0 for another ~12 months (when our next major release will be) which is quite a significant issue for the many hosting providers and Mautic users who, for security reasons, are required to only use versions under active support.
I appreciate it means you have to update your servers which may come at some inconvenience, however do you really want to be running an unsupported version of PHP which is not going to get any bug fixes or features, and is going to be completely unsupported in four months time anyway?
Time to plan those updates a bit more in advance before the end of active support perhaps 
If you’re on a bitnami build (AWS), looks like we have to wait until they build a new image. My one was at php 7.3. I tried to upgrade php but that went sideways! Had to restore from backup, no big deal.
I tried the very latest bitnami from July, that is still php 7.3 
Just a little patience needed.
I run Plesk on my servers which allows me to run multiple PHP versions at the same time easily.
I run Plesk as well, and didn’t know it could do that. Thank you!