Advanced Custom Fields Pro 6.4.0.1

Fix - ACF now detects when another plugin or theme is loading an incompatible version of Select2, and will fallback to a basic select field for the field type selection
Fix - Post Object, Page Link and Relationship field types now use a default post_status filter of any, matching the behavior prior to ACF 6.1. This can be edited per field in the field group admin or via the acf/fields/$field_type/query filters
Fix - Post Type and Taxonomy key generation now uses dashes rather than underscores
Fix - The "add first" text no longer appears when no search results are found for ACF field groups, post types or taxonomies

Fix - 'Create Terms' button for taxonomy fields now displays correctly
Fix - ACF JSON field group files which have unsupported keys (not beginning with group_) will now load as field groups
Fix - Renaming capabilities for post types will now set map_meta_cap to true solving an issue with assigning permissions to roles for that post type

Fix - Calls to acf_add_options_page after acf_add_local_field_group before acf/init will now behave correctly
i18n - All new ACF 6.1 strings are now correctly English (United States) by default