diff --git a/cases/all-classes.heta b/cases/all-classes.heta
index 3881d8d..79f6f66 100644
--- a/cases/all-classes.heta
+++ b/cases/all-classes.heta
@@ -90,109 +90,12 @@ pmid @ReferenceDefinition {
   suffix: /
 };
 
-pow @FunctionDefinition {
+pow #defineFunction {
   args: [x, y],
   expr: x^y
 };
 
-kDa @UnitDef {components: [
+kDa #defineUnit {components: [
   { kind: g, multiplier: 1e3, exponent: 1},
   { kind: mole, exponent: -1}
 ]};
-
-// simulations
-
-simple_task1 @SimpleTask {
-  model: sp1, // reference to space
-  subtasks: [
-    {saveat: [1,2,3], output_ids: [A, B, C]}
-    {saveat: [4,5,6], output_ids: [C]}
-  ],
-  type: simulation,
-  reassign: { // update constant values
-    const1: 3,
-    const2: 4.4
-  },
-  tspan: [0, 120], // time range
-  solver: {
-    alg: Rosenbrock23,
-    reltol: 1e-6,
-    abstol: 1e-12,
-    maxiters: 1e7,
-    dtmax: 0.1,
-    tstops: [] // force calculation in time points
-  },
-  data: {},
-  reduce: {}
-};
-
-simple_task2 @SimpleTask {
-  model: sp1,
-  subtasks: [
-    {saveat: [4,5,6]}
-  ]
-};
-
-multi_task1 @MultiTask { // unscoped
-  task_vec: [simple_task1, simple_task2],
-  sizes: {k1: 1, k2: 2}
-};
-
-// === fitting ===
-dts1 @SimpleData {
-  output_ids: [A, B, C], // depDataMarkers
-  indepData: ['t'], // indepDataMarker
-  t: [1, 2, 3], // indepData
-  val: [ // depData
-    [1, 1, 1],
-    [1, 1, 1],
-    [1, 1, 1]
-  ],
-  evid: [0, 0, 0]
-}
-
-l1 @SimpleTask {
-  model: sp1,
-  sizes: {}
-  subtasks: [{
-    data: dts1
-    reduce: ln_loss2
-  }],
-  reduce: sum
-};
-l2 @SimpleTask {
-  model: sp1,
-  sizes: {dose: 1}
-  subtasks: [{
-    data: dts2
-    reduce: ln_loss2
-  }],
-  reduce: sum
-};
-
-likelihood_sum @MultiTask {
-  tasks: [l1, l2],
-  reduce: sum
-};
-
-fitting_task1 @FittingTask {
-  inter_task: likelihood_sum,
-  fit_sizes: [k1, k2, k3],
-  fitter_opt: {
-    alg: LN_NELDERMEAD
-  }
-};
-
-dts1 @Observation {
-  kind: KineticsObservation,
-  indepDataMarker: t,
-  indepData: [0.1, 0.2, 0.3, 0.4, 0.5],
-  depDataMarkers: [x, y, z, s],
-  depData: [
-    [0, 0, 0, 0],
-    [0, 0, 0, 0],
-    [0, 0, 0, 0],
-    [0, 0, 0, 0],
-    [0, 0, 0, 0]
-  ]
-};
diff --git a/changelog.md b/changelog.md
index 3f5a256..e29dca4 100644
--- a/changelog.md
+++ b/changelog.md
@@ -3,6 +3,7 @@
 ## 0.4.1
 
 - `@StopSwitcher` as an experimental class
+- remove `@SimpleTask`
 
 ## 0.4.0
 
diff --git a/classes.md b/classes.md
index e0d5960..03b0b2d 100644
--- a/classes.md
+++ b/classes.md
@@ -18,7 +18,6 @@ Heta classes describes hierarchical types of Heta components.
 - [CSwitcher](#cswitcher)
 - [StopSwitcher](#stopswitcher) (experimental)
 - [Dose](#dose) (experimental)
-- [SimpleTask](#simpletask) (experimental)
 
 **Simple types**
 
@@ -403,44 +402,6 @@ dose1 @Dose {
 };
 ```
 
-## SimpleTask
-
-**Parent:** [Component](#component)
-
-*This is an experimental and not supported in most exports*
-
-`@SimpleTask` describes settings for simulation of the model based on particular namespace.
-
-| property | type | required | default | ref | description | 
-| ---------|------|----------|---------|-----|-------------|
-| subtasks | Subtask[] | true | | | Array of elements of type {saveat: \<number[]\>, output: \<string[]\>} |
-| tspan | number[] | | [0, 100] | | start and end point of simulation |
-| reassign | Dictionary | | {} | `Const` | reassignments of constants for the simulation |
-| solver.alg | string | | lsode | | method |
-| solver.reltol | number | | 1e-6 | | relative tolerance |
-| solver.abstol | number | | 1e-6 | | absolute tolerance |
-| solver.maxiters | number | | 1e5 | | maximum number of iteretions |
-| solver.dt | number | | 0 | | dt value |
-| solver.dtmin | number | | 0 | | dtmin value |
-| solver.dtmax | number | | 0 | | dtmax value |
-| solver.tstops | number[] | | [] | |time points for force stop |
-
-### Example
-
-```heta
-st1 @SimpleTask {
-    subtasks: [
-        { saveat: [0, 10, 100], output: [A, B, C] }
-    ],
-    tspan: [0, 120],
-    reassign: { p1: 10, p2: 0 },
-    solver: {
-        alg: lsoda,
-        abstol: 1e-9
-    }
-};
-```
-
 ## ID
 
 ID describes the string type which is used for idexing Heta components. ID type can be used for namespaces, identifiers and references.