Just to say I've updated to 3.7.4 and the error is still there.
My fix up to now has been to go back into a K2 item, click the Created and Published calendar button and click "Today", save and it's fine.
I will check out the Dev version.

Hello Tom,

Did you update to the DEV version?

Having somewhat of same issue. Installed joomla 3.7.4. My K2 version is 2.7.1.
Was not having this issue with k2 2.6.9.
I did download the DEV 2.8 and took the development site offline before installing the new k2 plugin 2.8 DEV.
I am not familiar with taking the dev site offline and so after installing 2.8, there were no items or categories in admin and site was offline even after i turned the offline off, therefore the site back online.

so, there were no items or categories whether the site was offline or online, once i installed the 2.8.
Any idea as to what might be going on?
I think the best thing for me is just to stay with 2.6.9 but just want to get an idea since i always want to ensure the site is using the latest stable versions.


Your help is greatly appreciated
s.

Did you unistall K2 before updating?
I hope you didn't. If you didn't try repairing your database's table.

I have the same problem with joomla 3.7.5 and K2 2.8. Interestingly, with some items the date is ok, and with a few years in the form -0001. Haw can I resolved it?

Which years were affected?