This is an attempt to document the various XMPP Extensions (​XEPs) supported by XMPP protocol plugin in libpurple.

XEP	notes
​XEP-0004: Data forms
​XEP-0012: Last Activity
​XEP-0020: Feature Negotiation	(for file transfers)
​XEP-0030: Service Discovery	(no UI implementation in Pidgin or Finch)
​XEP-0045: Multi-User Chat
​XEP-0047: In-band Bytestreams (IBB)
​XEP-0050: Ad-Hoc Commands
​XEP-0054: vcard-temp
​XEP-0055: Jabber Search
​XEP-0060: Publish-Subscribe	(partial/minimal support, used for PEP)
​XEP-0065: SOCKS5 Bytestreams
​XEP-0066: Out of Band Data
​XEP-0071: XHTML-IM
​XEP-0077: In-Band Registration
​XEP-0084: User Avatar	v1.1 (grok received notifications with v0.12 namespace)
​XEP-0085: Chat State Notifications
​XEP-0092: Software Version
​XEP-0095: Stream Initiation
​XEP-0096: SI File Transfer	(SOCKS5 bytestreams, IBB)
​XEP-0100: Gateway Interaction	minimal support in Pidgin/Finch?
​XEP-0107: User Mood
​XEP-0115: Entity Capabilities	v1.5 since 2.6.0
​XEP-0118: User Tune
​XEP-0124: Bidirectional-streams Over Synchronous HTTP (BOSH)	Since 2.6.0
​XEP-0153: vCard-Based Avatars
​XEP-0156: Discovering Alternate XMPP Connection Methods	partial support since 2.6.0 (for BOSH)
​XEP-0163: Personal Eventing Protocol
​XEP-0166: Jingle	Since 2.6.0
​XEP-0167: Jingle RTP Sessions	Since 2.6.0 when compiled with voice and video support
​XEP-0172: User Nickname
​XEP-0174: Serverless Messaging	(via the Bonjour prpl)
​XEP-0176: Jingle ICE-UDP Transport Method	Since 2.6.0 when compiled with voice and video support
​XEP-0177: Jingle Raw-UDP Transport Method	Since 2.6.0 when compiled with voice and video support
​XEP-0191: Simple Communications Blocking	Partial
​XEP-0199: XMPP Ping
​XEP-0202: Entity Time
​XEP-0203: Delayed Delivery
​XEP-0206: XMPP Over BOSH	Since 2.6.0
​XEP-0224: Attention
​XEP-0231: Bits of Binary	(used for custom emoticons)
​XEP-0232: Software Information
​XEP-0245: The /me Command
​XEP-0249: Direct MUC Invitations
​XEP-0256: Last Activity in Presence	Since 2.6.0

(INCOMPLETE)