Request upgrade of search_api from 1.15 to 1.19 so search_api_solr ^4.0.1 - 4.1.x can be installed

Time moving forward ... search_api 1.19 is the latest version in between

Hope to move to move it forward: https://github.com/goalgorilla/open_social/pull/2307

Clearing random tags (please see the issue tag guidelines) and moving to 10.2.x given the impact of this module update.

Release notes for the new versions are

• https://www.drupal.org/project/search_api/releases/8.x-1.16
• https://www.drupal.org/project/search_api/releases/8.x-1.17
• https://www.drupal.org/project/search_api/releases/8.x-1.18
• https://www.drupal.org/project/search_api/releases/8.x-1.19

Notable release note snippets

8.x-1.16

Due to #3111635: Duplicate dependencies, new index exports will differ substantially from earlier versions after this release. It is advised to re-export all exported search indexes, stored in any config directory or the like, after updating to this release, to avoid confusion when actual changes are later made.

This means we will need to re-create our social*.index.*.yml files. Doing this only for the install folder should be fine. Search API will update the in-database config for us.

Users of the Database server backend plugin are encouraged to review #2873023: Special characters are always ignored in searches on DB backend and see whether it improves or impairs their fulltext search capabilities. (Especially if searching for special characters should be allowed.)

This shouldn't require any action from our side but some of our international sites may want to take extra care during the update to see the actual impact for them.

A follow-up will need to be created for #3103585: Convert hook_search_api_db_query_alter() to an event so that we stay compatible with future versions.

8.x-1.17

No changes of note

8.x-1.18

#2007692: Changes in related entities don't lead to proper re-indexing means that we may be able to remove _social_search_retrigger_profile and social_search_user_update altogether although this needs some testing.

8.x-1.19

Fixes a critical regression in 1.18 but otherwise no changes of interest.