There are 2 separate things going on here - a warning about the php-apc module, and the "person" entity type error. I'll answer the second part first.
The short version is: try capitalizing it to Person, as it is in the example CSV.
The explanation: some of our older import code is a bit too exacting - it does not normalize case when looking for existing terms and, even though the taxonomy terms are user-editable, the older code sometimes throws an error instead of simply creating a new term and reporting in the console (as you would expect) when no existing term matches. I suspect this is happening because of this. I'll try to test and file a bug report if so - AtoM should a) be able to match "person" with the existing term "Person" and b) even if "Person" didn't exist in your installation, it should be able to create a new term and continue without halting the import.
In the meantime, see if capitalizing it helps you workaround this issue.
Now, the apc warning:
php-apcu is a PHP extension we use in AtoM that helps with caching. In this section of the 2.5 documentation, you can see where we install it as php-apcu:
If you look at the sample atom.conf configuration block in that section as well, you can see where we set some APC parameters. The instructions are the same in the 2.5 Ubuntu 16.04 documentation.
You mentioned that you've just upgraded from 2.4. One important thing to consider: there are changes in packages between versions, based on what was supported in Ubuntu at the time. Looking back through our documentation it seems like we had the following:
- 2.4 on Ubuntu 14.04 - php-apc
16.04 - php-apcu & php-apcu-bc
16.04 and 18.04 - php-apc
I don't know enough about PHP and Ubuntu packages and apcu in general to explain all of this, but php-apcu-bc is a "backwards compatibility" version that was a community release to support some functionality with older PHP versions.
When using php 7.2 (Ubuntu 18.04 or Centos 7), the apcu_bc extension is not only not needed, but also breaks atom. We should update the install instructions in order to add the following packages:
- Ubuntu 18.04: php-apcu
- Centos 7: rh-php72-php-pecl-apcu
Also, in the atom25-1604 vm, apcu_bc doesn't seem installed, so I think we should remove the paragraph from the install instructions.
So: if you've just upgraded, but installed the new 2.5 version on the same server as your 2.4 instance, then it's possible that the problem is that php-apcu-bc is still installed. I'd suggest asking your IT team to take a look at that first.
Make sure you also check what version of PHP you have installed - if you're using Ubuntu 18.04, our documentation recommends PHP 7.2. If you're using Ubuntu 16.04, we recommend PHP 7.0 - though I believe that PHP7.2 should work on a 16.04 installation as well. In the 2.4 release we were still supporting Ubuntu 14.04, which required the use of PHP 5.x - so again, make sure if you've upgraded on the same server, that you are using the correct PHP version.
Let me know if this helps!