diff --git a/docs/2_4_common_schema.adoc b/docs/2_4_common_schema.adoc
index 165ee3c09..1a6eb6d91 100644
--- a/docs/2_4_common_schema.adoc
+++ b/docs/2_4_common_schema.adoc
@@ -940,7 +940,7 @@ The algebraic relationship to the <> can be defined via the <> and their <>, <>, <> or <>.
+* continuous <> and their <>, <>, <> or <>.
These variables are listed in the ``. +
* [[localClock,`local clock`]] internal, intermediate variables or local clocks which can be read for debugging purposes and are not listed in the ``.
@@ -1071,6 +1071,17 @@ Variables with <> <> must not be marked with <> and this attribute is a value reference to the variable with the previous value.
+Only clocked variables (they are listed in at least one of the <> lists) may have the <> attribute.
+Only variables with <> may have a previous value.
+
+_[For example, if `previous == 3` for variable `8`, then variable `3` is the previous value of variable `8`. See also <>._
+_Note: This is reverse compared to the <> attribute.]_
+
|====
If <> is not present, its value is defined by <> based on the values of <> and <> (default [.underline]#underlined#):
@@ -1675,11 +1686,13 @@ Beside the knowns the derivatives also depend on the "frozen" variables (= varia
The functional dependency is defined as (dependencies of variables that are fixed in Event and <> and at communication points are not shown): +
latexmath:[{\dot{\mathbf{x}_c} := \mathbf{f}_{\mathit{der}}(\mathbf{x}_c, \mathbf{u}_c, \mathbf{u}_d, t, \mathbf{p}_{\mathit{tune}})}]
-|`DiscreteTimeState`
+|`ClockedState`
|
-[[DiscreteTimeState,``]]
-XXX // TODO: Add description, see #1287 on github. +
-XXX // TODO: This should likely be Locals (ask ZIrina), to allow dependency definitions for modelPartitions (to input clocks) for all local variables
+[[ClockedState,``]]
+A <> is part of the discrete state of a model partition and represented by a <> variable.
+To which clock or clocks it belongs is described in <>.
+Each <> must have the attribute <> to represent the previous value of this <>.
+All <> must have <>.
|`InitialUnknown`
|
@@ -1722,11 +1735,19 @@ _The ordering of the variables in this list is defined by the exporting tool.]_
For Co-Simulation, elements <> are ignored.
_[If an FMU supports both Model Exchange and Co-Simulation, then the <> elements might be present, since it is needed for Model Exchange.]_
+|`Clock`
+|
+[[ClockElement,``]]
+List of all clocks and their clocked variables.
+All variables referenced by these lists must have <>.
+A clocked variable my depend on multiple clocks and may therefore be listed in multiple <> elements.
+_[More rigorous importers requiring a variable to be dependent on a single clock can reject FMUs violating this restriction.]_
+
|====
-Elements <