Version 1.8.0
(??? from http://code.elgg.org/branches/1.8/)

 User-visible changes:

 Generic API changes:
  * Added elgg_instanceof().
  * Added remove_subtype() and update_subtype().
  * Added elgg_format_url()

 UI/UX API changes:
  * Added elgg_push_breadcrumb(), elgg_pop_breadcrumb(), and elgg_get_breadcrumbs().
  * Added navigation/breadcrumbs.
  * Added sticky form support with elgg_make_sticky_form(), 
    elgg_clear_sticky_form(), elgg_is_sticky_form(), and elgg_get_sticky_value().



Version 1.7.0
(March 2, 2010 from http://code.elgg.org/elgg/trunk/)

 User-visible changes:
  * UTF8 now saved correctly in database. #1151
  * Unit tests added to System diagnostics.
  * Debug values output to screen when enabled in admin settings.
  * Users can now log in from multiple computers or browsers concurrently.
  * Misconfigured plugins no longer break the site. #1454
  * User display names cannot have HTML or be longer than 50 characters.
  * New search system.

 Bugfixes:
  * Searching by tag with extended characters now works. #1151, #1231
  * Searching for entities works properly with case-insensitive metadata. #1326
  * Invalid views now default to 'default' view. #1161.
  * Metadata cache now handles a 0 string. #1227
  * ElggPlugin get() now works with 0. #1286
  * Metadata __isset() now works for falsy values (except NULL). #1414
  * clear_plugin_setting() now only clears a single setting.
  * Submenu entries are correctly calculated after a simplecache refresh.

 API changes:
  * New plugin hook system:unit_test for adding files to unit tests.
  * $is_admin global deprecated; use elgg_set_ignore_access() instead.
  * Deprecated get_entities().  Use elgg_get_entities().
  * Deprecated get_entities_from_metadata().  Use elgg_get_entities_from_metadata().
  * Deprecated get_entities_from_relationship() and g_e_f_relationships_and_meta().  Use elgg_get_entities_from_relationship().
  * Deprecated get_entities_from_access_id(). Use elgg_get_entities_from_access_id().
  * Deprecated get_entities_from_annotations().  Use elgg_get_entities_from_annotations().
  * Reorganized directory file path to rely on GUID instead of username.
  * annotation_id column added to the river database table.
  * remove_from_river_by_annotation() added.
  * unregister_elgg_event_handler() and unregister_plugin_hook() added. #1465
  * clear_all_plugin_settings() added.
  * get_entity_relationships() supports inverse relationships. #1472.
  * can_write_to_container() can be overridden with the container_permissions_check hook. #1164 (part 2).
  * Deprecated search_for_*().
  * Deprecated search_list*().
  * Added elgg_deprecated_notice().
  * ElggEntity::countEntitiesFromRelationship() supports inverse relationships. #1325
  * delete_relationship() triggers the hook delete:relationship and passes the relationship object. #1213
  * added ElggEntity::removeRelationship(). #1376.
  * get_entity_dates() supports order by. #1406.
  * Added elgg_http_add_url_query_elements().
  * Added elgg_register_tag_metadata_name() and elgg_get_registered_tag_metadata_names();
  * Added ElggEntity::getTags().
  * Added elgg_add_action_tokens_to_url().

 Services API:
  * Separated user and api authenticate processing
  * hmac signature encoding now compatible with OAuth
  * New plugin hook api_key:use for keeping stats on key usage
  * New plugin hook rest:init so plugins can configure authentication modules
  * Moved auth.gettoken to POST for increased security
  * Fixed REST POST bug #1114
  * Fixed #881, #1214, #1215, #1216, #1217, #1218, #1219, #1220, #1298, #1364