The MergedFreeBusy element is an optional child element of the Availability element in ResolveRecipients command responses that specifies the free/busy information for the users or distribution list identified in the request.

All elements referenced in this section are defined in the ResolveRecipients namespace.

Command request/response

Parent elements

Child elements

Data type

Number allowed

ResolveRecipients command response (section

Availability (section


string ([MS-ASDTYPE] section 2.7)

0...1 (optional)

The MergedFreeBusy element value string has a maximum length of 32 KB. To retrieve more than 32 KB of availability data, the client MUST issue a new request with the appropriate start time and end time.

Each digit in the MergedFreeBusy element value string indicates the free/busy status for the user or distribution list for every 30 minute interval. The following table lists the valid values.










Out of Office (OOF)


No data

A string value of "32201" would represent that this user or group of users is out of the office for the first 30 minutes, busy for the next hour, free for 30 minutes, and then has a tentative meeting for the last 30 minutes. If the user or group of users has a change in availability that lasts less than the interval value of 30 minutes, the availability value with the higher digit value is assigned to the whole interval period. For example, if a user has a 25 minutes of free time (value 0) followed by 5 minutes of busy time (value 2), the 30 minute interval is assigned a value of 2 in the server response.

The server determines the number of digits to include in the MergedFreeBusy element by dividing the time interval specified by the StartTime element (section value and the EndTime element (section value by 30 minutes, and rounding the result up to the next integer.

The MergedFreeBusy element value string is populated from the StartTime element value onwards, therefore the last digit represents between a millisecond and 30 minutes. A query for data from 13:00:00 to 13:30:00 returns a single digit but a query from 12:59:59 to 13:30:00 or 13:00:00 to 13:30:01 returns two digits.

Any appointment that ends inside a second of the interval requested shall impact the digit representing that timeframe. For example, given a calendar that contains a 5 minute OOF appointment from 12:00 to 12:05, and is free the rest of the day, queries would result in the following:

  • If a query is made for 12:00:00 to 13:00:00, the result is "30", where each digit represents exactly 30 minutes.

  • If a query is made for 12:04:59 to 13:00:00, the result is "30", where the "0" maps to 12:34:59 to 13:00:00.

  • If a query is made for 12:05:00 to 13:00:00, the result is "00" where the second 0 maps the last 25 minutes of the interval.

The client MUST consider daylight saving time transitions and might need to add or remove time intervals from the MergedFreeBusy element value string, as there are days that have more or less than 24 hours.

If the Availability element is included in the response, the response MUST also include the Status element (section The MergedFreeBusy element is also included if the Status element value indicates success.

Protocol Versions

The following table specifies the protocol versions that support this element. The client indicates the protocol version being used by setting either the MS-ASProtocolVersion header, as specified in [MS-ASHTTP] section, or the Protocol version field, as specified in [MS-ASHTTP] section, in the request.

Protocol version

Element support