+ For more information, see [Developer Guide: APIv4 Usage](https://docs.civicrm.org/dev/en/latest/api/v4/usage/)
+ and [Differences between APIv3 / APIv4](https://docs.civicrm.org/dev/en/latest/api/v4/differences-with-v3/).
+
+- **Improve obsolete extension management
+ ([15352](https://github.com/civicrm/civicrm-core/pull/15352))**
+
+ This change improves the extension UI by marking obsolete extensions as
+ "Obsolete", removing the Install and Enable actions for obsolete extensions
+ and completely uninstalling obsolete extensions during core upgrades.
+
+- **Check requirements before upgrading extensions via the UI
+ ([15450](https://github.com/civicrm/civicrm-core/pull/15450))**
+
+ Improves user experience by checking for required dependencies when upgrading
+ an extension. If the extension version being upgraded to requires a dependency
+ throws a helpful error.
+
+- **Upgrader: handle missing obsolete extensions
+ ([15343](https://github.com/civicrm/civicrm-core/pull/15343))**
+
+ Improves the mechanism for auto-disabling obsolete extensions during the
+ upgrade process to disable extensions even if they are missing.
+
+- **Updated entityRefFilters hook to support alter form create links
+ ([15231](https://github.com/civicrm/civicrm-core/pull/15231))**
+
+ Improves the `hook_civicrm_entityRefFilters()` to support altering create
+ links like "New Household" and "New Individual".
+
+- **Add getdisplayvalue api with unit test.
+ ([15335](https://github.com/civicrm/civicrm-core/pull/15335))**
+
+ Adds a new action `getdisplayvalue` to the `CustomValue` entity.
+
+- **Add in an index on geo_code_1 and geo_code_2 to assist with distance and
+ other queries ([15361](https://github.com/civicrm/civicrm-core/pull/15361))**
+
+ Adds an index to `geo_code_1` and `geo_code_2` to help calculation
+ queries based on latitude and longitude.
+
+- **Allow columns in relationship table to be modified by searchColumns hook
+ ([14184](https://github.com/civicrm/civicrm-core/pull/14184))**
+
+ Allow columns in the relationship table to be modified by
+ `hook_civicrm_searchColumns()`. This allows developers to modify the columns
+ shown to the user on the Contact relationships tab.
+
+- **Per agreement in NYC sprint, add status check is_active to table
+ ([dev/core#1295](https://lab.civicrm.org/dev/core/issues/1295):
+ [15409](https://github.com/civicrm/civicrm-core/pull/15409) and
+ [15416](https://github.com/civicrm/civicrm-core/pull/15416))**
+
+ Adds an `is_active` field to the `civicrm_status_pref` table which is
+ api-accessible but not UI exposed. This field enables developers and system
+ administrators to turn off a system check.
+
+- **Declare metadata for component payment fields on export
+ ([15243](https://github.com/civicrm/civicrm-core/pull/15243))**
+
+ Adds metadata for component payment fields.
+
+- **Add CRM_Utils_JS::encode function
+ ([15285](https://github.com/civicrm/civicrm-core/pull/15285))**
+
+ Adds a utility function for encoding javascript strings which gives an output
+ that looks more like handwritten javascript and less like the overly-quoted
+ `json_encode`.
+
+- **CRM_Utils_JS - Improve encode handling of strings
+ ([15295](https://github.com/civicrm/civicrm-core/pull/15295))**
+
+ Improves test scenarios and tweaks the encode and decode functions to handle
+ strings better.
+
+- **Event Info/Contribution Page Smarty templates are inconsistent and ugly
+ ([dev/core#1225](https://lab.civicrm.org/dev/core/issues/1225):
+ [15168](https://github.com/civicrm/civicrm-core/pull/15168))**
+
+ Improves the HTML of the smarty templates that power the "Event Info" and
+ "Contribution Page". The pages appear the same to the end user but the
+ underlying HTML is cleaner.
+
+### CiviContribute
+
+- **Update Online Contributions section of configuration checklist
+ ([dev/core#1259](https://lab.civicrm.org/dev/core/issues/1259):
+ [15317](https://github.com/civicrm/civicrm-core/pull/15317))**
+
+ Improves the user experience of the Configuration Checklist Online
+ Contributions section, specifically: only shows this section if CiviContribute
+ is enabled, removes the system workflow templates list item, improves links to
+ documentation.
+
+- **Add trxn_id as a parameter on Payment.get
+ ([15417](https://github.com/civicrm/civicrm-core/pull/15417))**
+
+ Adds `trxn_id` as a viable parameter to the API call `Payment.get`.
+
+### CiviMail
+
+- **Mailing API - Expose option list for `header_id` and `footer_id`
+ ([15325](https://github.com/civicrm/civicrm-core/pull/15325))**
+
+ Improves the Mailing API `getoptions` and `getfields` actions to work for the
+ fields `header_id` and `footer_id`.
+
+- **Add unique name to mailing_job.start_date
+ ([15210](https://github.com/civicrm/civicrm-core/pull/15210))**
+
+ Adds metadata to the `MailingJob.start_date` field to prepare this field to
+ use datepicker.