Warning: Use of undefined constant self - assumed 'self' (this will throw an Error in a future version of PHP) in system/modules/_autoload/NamespaceClassLoader.php on line 86
#0 system/modules/_autoload/NamespaceClassLoader.php(86): __error()
#1 system/modules/_autoload/NamespaceClassLoader.php(74): NamespaceClassLoader::addContaoRoot()
#2 system/modules/notification_center/config/autoload.php(26): NamespaceClassLoader::addClassMap()
#3 system/modules/core/library/Contao/ClassLoader.php(222): include('/var/www/previe...')
#4 system/initialize.php(105): Contao\ClassLoader::scanAndRegister()
#5 index.php(16): require('/var/www/previe...')
#6 {main}

Warning: Use of undefined constant self - assumed 'self' (this will throw an Error in a future version of PHP) in system/modules/_autoload/NamespaceClassLoader.php on line 86
#0 system/modules/_autoload/NamespaceClassLoader.php(86): __error()
#1 system/modules/_autoload/NamespaceClassLoader.php(74): NamespaceClassLoader::addContaoRoot()
#2 system/modules/isotope/config/autoload.php(27): NamespaceClassLoader::addClassMap()
#3 system/modules/core/library/Contao/ClassLoader.php(222): include('/var/www/previe...')
#4 system/initialize.php(105): Contao\ClassLoader::scanAndRegister()
#5 index.php(16): require('/var/www/previe...')
#6 {main}

2-1-2 complete system