After upgrading Wordpress and associated plugins to the latest version on a dev server and migrating the source files and database to the production server, the data from ACF is different.

prod and dev server (dev is a Vagrant clone of prod)

CentOS 6.9
Apache 2.4
PHP 5.6 (php-fpm using mod_proxy_fcgi)
MySQL 5.7
DocRoot: /home/user/example

Upgrades:

Wordpress:        3.8.4  => 4.9.8
ACF:              4.4.12 => 5.7.7
ACF Repeater:     1.0.1  => 2.1.0
ACF Page Options: 1.0.1  => 2.1.0

UPDATE (removed unneeded information)

I managed to migrate the data with WP_CRON disabled. After I re-enabled WP_CRON, I encounter the issue with the data.

Looking at the data operations when manually executing wp-cron.php, I've determined that the issue is caused by wp_split_shared_term_batch.

Comparing the wp_options, wp_terms and wp_taxonomy tables from before and after running wp-cron.php shows a lot of changes with the ACF data.

• Assigns a different term_id and parent in the wp_taxonomy table.
• Removes and changes multiple ACF values in wp_options
• Adds a new _split_terms row in wp_options
• Duplicated multiple values in wp_terms

After upgrading Wordpress and associated plugins to the latest version on a dev server and migrating the source files and database to the production server, the data from ACF is different.

prod and dev server (dev is a Vagrant clone of prod)

CentOS 6.9
Apache 2.4
PHP 5.6 (php-fpm using mod_proxy_fcgi)
MySQL 5.7
DocRoot: /home/user/example

Upgrades:

Wordpress:        3.8.4  => 4.9.8
ACF:              4.4.12 => 5.7.7
ACF Repeater:     1.0.1  => 2.1.0
ACF Page Options: 1.0.1  => 2.1.0

UPDATE (removed unneeded information)

I managed to migrate the data with WP_CRON disabled. After I re-enabled WP_CRON, I encounter the issue with the data.

Looking at the data operations when manually executing wp-cron.php, I've determined that the issue is caused by wp_split_shared_term_batch.

Comparing the wp_options, wp_terms and wp_taxonomy tables from before and after running wp-cron.php shows a lot of changes with the ACF data.

• Assigns a different term_id and parent in the wp_taxonomy table.
• Removes and changes multiple ACF values in wp_options
• Adds a new _split_terms row in wp_options
• Duplicated multiple values in wp_terms

• advanced-custom-fields
• terms
• wp-cron

1 Answer 1

After attempting many upgrades of various WP and ACF versions, I have concluded that WP 3.8 to 4.2 with ACF 4 data can not be upgraded to WP 4.3+ withACF 5.

Reason

WP 4.3 introduced a feature called split_shared_term, which affects the data used by ACF 5. ACF 4 stores the data in a manner that is re-indexed by the WP 4.3+ term splitting once it is upgraded to ACF 5. Resulting in ACF being unable to find the assigned indexes of those split terms.

I believe this is an issue with the ACF 5 database upgrade, not fully accounting for the split terms that WP 4.3+ will create from the ACF 4 data.

I have reached out to the ACF support team regarding the issue, with a general response on how the upgrade to ACF 5 may not have completed fully or an error occurred. As per their suggestion by changing the ACF version in the wp_options table and forcibly running the database upgrade again, results in duplicate data, but still invalid index references.

I managed to find a plugin that seems to mitigate the issue in ACF 4 when upgrading from WP 4.0 to 4.3, but does not work for ACF 5. The plugin is called acf-split-terms on github.

For more details about the split terms, please see https://make.wordpress/core/2015/02/16/taxonomy-term-splitting-in-4-2-a-developer-guide/