<varlistentry>
<term><varname>_SOURCE_REALTIME_TIMESTAMP=</varname></term>
+ <term><varname>_SOURCE_MONOTONIC_TIMESTAMP=</varname></term>
<listitem>
- <para>The earliest trusted timestamp of the message, if any
- is known that is different from the reception time of the
- journal. This is the time in microseconds since the epoch
- UTC, formatted as a decimal string.</para>
+ <para>The earliest trusted timestamp of the message, if any is known that is different from
+ the reception time of the journal. These are the <constant>CLOCK_REALTIME</constant> and
+ <constant>CLOCK_MONOTONIC</constant> clocks in microseconds, formatted as decimal strings.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>_SOURCE_BOOTTIME_TIMESTAMP=</varname></term>
+ <listitem>
+ <para>The earliest trusted timestamp of the message in <constant>CLOCK_BOOTTIME</constant> clock.
+ For details, refer to <varname>_SOURCE_MONOTONIC_TIMESTAMP=</varname>.</para>
+
+ <xi:include href="version-info.xml" xpointer="v257"/>
</listitem>
</varlistentry>