When updating ACF to version 5.7.6 or later, afterwards, click on plugins and you will be shown the following notification “Database Upgrade Required”. Make sure to click “upgrade database”, otherwise your site will look broken.

ACF has rolled out their new plugin meaning that ACF: Options Page and ACF: Repeater Field plugins are no longer supported in the new ACF plugin. That means your about page, the slider on the home page, and the options settings on the backend (details, contact, home form) won’t display at all or incorrectly. For everything to function properly again, you’ll need to purchase ACF pro for $25 (https://www.advancedcustomfields.com/pro) and deactivate the other plugins. Then, install ACF pro and you’ll be set to go.

Step by step:
1. Purchase ACF Pro
2. Deactivate ACF
3. Delete ACF: Repeater Fields and ACF: Options Page (these have to be deleted in the backend as they cannot be deactivated and deleted from the wordpress admin side for some reason). For this you can use filezilla and get into the wordpress file structure. Go to your site then wp-content->plugins and delete the corresponding two ACF entries. Alternatively, you can install a file manager plugin on the admin side of wordpress to accomplish the same result.
4. Install ACF Pro
5. Activate ACF Pro
6. Make sure everything is working properly again
7. (Optional): Delete ACF

If any of this doesn’t make sense to you, please don’t attempt it. Find a qualified developer who knows what they’re doing.

Afterwards, you will notice an error that the theme is missing plugins. The issue here is that the notification cannot be dismissed by default. Luckily however, we have already covered this issue and found a workaround, which you can find here: https://support27.com/blog/732