Server implementations can aid to resolve this conflict by automatically putting avatars uploaded with XEP-0084 into XEP-0153 storage and vice versa. This allows clients to use the more efficient XEP-0084 for uploading avatars and XEP-0153 to retrieve avatars in Multi-User Chats.
The conversion is transparent to the uploading entity. However an entity might want to discover if a service will be performing the conversion from XEP-0084 to XEP-0153 since using vCard-Based Avatars will make the uploaded avatar publicly available. (See the »Security Considerations« section of this XEP.)
+The conversion is transparent to the uploading entity. However an entity might want to discover if a service will be performing the conversion from XEP-0084 to XEP-0153 since using vCard-Based Avatars will make the uploaded avatar publicly available. (See the “Security Considerations” section of this XEP.)
The service MUST include a &xep0030; feature of "urn:xmpp:pep-vcard-conversion:0" on the account.
The »Business Rules« section of XEP-0153 tells entities to include a hash of the vCard avatar in their presence. However this requires clients to retrieve the avatar on every connect to calculate the hash. To avoid this, services MUST include the hash on behalf of their users in every available presence that does not contain an empty photo element wrapped in an x element qualified by the 'vcard-temp:x:update' namespace. Empty x elements qualified by the 'vcard-temp:x:update' namespace (those without a photo element as child) MUST be overwritten. Presences where the content of the photo element is not empty and not equal to the hash calculated by the service MAY be overwritten.
+The “Business Rules” section of XEP-0153 tells entities to include a hash of the vCard avatar in their presence. However this requires clients to retrieve the avatar on every connect to calculate the hash. To avoid this, services MUST include the hash on behalf of their users in every available presence that does not contain an empty photo element wrapped in an x element qualified by the 'vcard-temp:x:update' namespace. Empty x elements qualified by the 'vcard-temp:x:update' namespace (those without a photo element as child) MUST be overwritten. Presences where the content of the photo element is not empty and not equal to the hash calculated by the service MAY be overwritten.