2.2.84 [RFC5545] Section 3.8.4.7 Unique Identifier
V0177:
The specification states that non-standard property parameters can be specified on the UID property.
Microsoft Office Outlook 2007, Microsoft Outlook 2010, Microsoft Outlook 2013, Microsoft Outlook 2016, Microsoft Outlook 2019
Outlook exports no parameters on the UID property. Outlook ignores all parameters on the UID property.
V0178:
The specification states that the UID property MUST be specified in VEVENT, VTODO, VJOURNAL, and VFREEBUSY components, and that calendaring and scheduling applications MUST generate this property in VEVENT, VTODO, and VJOURNAL components.
Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019
Outlook exports exactly one UID property on VEVENT components. Outlook does not export VTODO, VJOURNAL, or VFREEBUSY components.
On import, Outlook ignores all instances of UID outside of VEVENT components. If multiple UID instances are found in a VEVENT, all but the first are ignored. If the UID property is missing in a VEVENT, Outlook continues to import it. However, since UID is crucial to certain functionality, this can lead to undesirable behavior if the VEVENT represents a meeting or recurring appointment.
V0179:
The specification states that the UID MUST be a globally unique identifier, and the generator of the identifier MUST guarantee that the identifier is unique.
Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019
On export, Outlook generates unique values for UID. On import, Outlook only relies on UID values for meetings and recurring appointments within the user's calendar. As long as the value is unique in the scope of all meetings and recurring appointments on the user's calendar, Outlook parses the data correctly.
V0180:
The specification states that it is recommended that the identifier's right-hand side contain some domain identifier.
Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019
On export, Outlook round-trips the UID property if the appointment originated from an iCalendar object. For appointments originating elsewhere, Outlook exports hexadecimal encoding of internal IDs.
On import, Outlook can import any valid UID, whether or not this recommendation was followed.
V0181:
The specification states that though other algorithms will work, it is RECOMMENDED that the right-hand side of the UID contain some domain identifier such that the generator can guarantee the left-hand side within the scope of that domain.
Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019
On export, Outlook round-trips the UID property if the appointment originated from an iCalendar object. For appointments originating elsewhere, Outlook does not append any domain identifier to the UID.
On import, Outlook can import any valid UID, whether or not this recommendation was followed.
V0182:
The specification states that implementations MUST be able to receive and persist values of at least 255 characters for the UID property.
Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019
On export, Outlook round-trips the UID property of an appointment originated from an iCalendar object, so there is no explicit limit to the size of the UID that Outlook can export. For appointments originating in an Outlook .PST or .OST file, the largest UID Outlook exports is 140 bytes.
See section 2.1.10 for import behavior.