Remove decorators for "Legacy Delayed Delivery" (XEP-91) in favor of Delayed Delivery (XEP-203)
Description
The (only ?) difference between XEP-91 and XEP-203 is the format of the timestamps. XEP-203 states that "Implementations that support XEP-0091 should support the protocol defined herein as soon as possible, but should continue to support the protocol defined in XEP-0091 for backwards compatibility until the status of that specification is changed to Obsolete." XEP-91 is now obsolete, so we can remove the compatibility code.
Note that we will use XmppDateTime.parseDate() to parse the timestamp, which also supports the legacy XEP-91 format. So Smack will still be able to parse legacy delayed delivery messages.
Also add DelayedDeliverManager.isDelayedStanza(Packet) predicate, in order to filter stanzas with delayed delivery information easily.
The (only ?) difference between XEP-91 and XEP-203 is the format of the timestamps. XEP-203 states that "Implementations that support XEP-0091 should support the protocol defined herein as soon as possible, but should continue to support the protocol defined in XEP-0091 for backwards compatibility until the status of that specification is changed to Obsolete." XEP-91 is now obsolete, so we can remove the compatibility code.
Note that we will use XmppDateTime.parseDate() to parse the timestamp, which also supports the legacy XEP-91 format. So Smack will still be able to parse legacy delayed delivery messages.
Also add DelayedDeliverManager.isDelayedStanza(Packet) predicate, in order to filter stanzas with delayed delivery information easily.
http://xmpp.org/extensions/xep-0091.html
http://xmpp.org/extensions/xep-0203.html