Configuration
variable_get() has been removed.
Documentation
Files Affected
variable_set() has been removed.
Documentation
Files Affected
Database
drupal_write_record() has been removed.
Documentation
Files Affected
Entity API
entity_save() has been removed.
Documentation
Files Affected
node_load() has been removed.
Documentation
Files Affected
node_save() has been removed.
Documentation
Files Affected
Field API
The Field API CRUD functions have been removed.
Documentation
Files Affected
Form API
form_error() is now a method of FormStateInterface.
Documentation
Files Affected
form_set_error() is now a method of FormStateInterface.
Documentation
Files Affected
Info File
Module info files' core key must have a value of 8.x.
Documentation
Files Affected
Info files must contain a type key.
Documentation
Files Affected
Modules no longer declare classes in their info file.
Documentation
Files Affected
Menu/Routing
hook_menu() has been removed from Drupal 8.
Documentation
Files Affected
Miscellaneous
Many common functions, shared variables, and constants have been renamed.
Documentation
Classes must be PSR-4 compliant.
Documentation
Automated web tests must be in a PSR-4 namespace, and unit tests must be converted to PHPUnit.
Documentation
Rendering
drupal_add_css() has been removed.
Documentation
Files Affected
drupal_add_js() has been removed.
Documentation
Files Affected
System
hook_watchdog() has been replaced by a PSR-3 compatible logging system.
Documentation
Files Affected
conf_path() has been removed.
Documentation
Files Affected
drupal_goto() has been removed.
Documentation
Files Affected
drupal_http_request() has been replaced by Guzzle.
Documentation
Files Affected
drupal_chmod() is now a method of the file_system service.
Documentation
Files Affected
drupal_realpath() is now a method of the file_system service.
Documentation
Files Affected
file_uri_scheme() is now a method of the file_system service.
Documentation
Files Affected
l() has been removed.
Documentation
Files Affected
module_invoke_all() is now a method of the module_handler service.
Documentation
Files Affected
file_get_stream_wrappers() has been removed.
Documentation
Files Affected
get_t() has been removed.
Documentation
Files Affected
url() has been removed.
Documentation
Files Affected
watchdog() has been removed.
Documentation
Files Affected
Static permissions are now defined in MODULE.permissions.yml.
Documentation
Files Affected

This issue can be fixed automatically.