CardDAV feature

[phoneuser]

Adding CardDAV feature would simplify the the use of unified phonebooks for home/small offices as many home/small offices would use it across mobile devices (iPhone, Android, mail clients). LDAP and similar features are enterprise standard protocols which are rarely used by home/small offices because of their complexity when it comes to server configuration, whereas XML phonebook is not as flexible as CardDAV because it's limited to a range of IP phones and can't be used on other devices (e.g. PC) without writing various conversion scripts. There are plenty of free and commercial CardDav contact services such as google and others.
Therefore having CardDAV feature on Yealink phones will allow a unified address book to be used seamlessly across various devices without any complex configuration, i.e. out of the box. CardDAV clients are already preinstalled on iPhones and Android devices so using any online CardDAV service across all devices will be easy and straightforward for all users.