diff --git a/backendless.d.ts b/backendless.d.ts
index c521e6ff..a7463b49 100644
--- a/backendless.d.ts
+++ b/backendless.d.ts
@@ -612,10 +612,12 @@ declare module Backendless {
          * @type: Function
          */
 
+        type Execution = 'activateAny' | 'activateAll' | string
+
         function activateFlow(flowName: string, initialData?: object): Promise<void>
         function activateFlowById(flowId: string, initialData?: object): Promise<void>
         function activateFlowTrigger(flowName: string, triggerName: string, data?: object): Promise<void>
-        function activateFlowTriggerById(flowId: string, triggerId: string, data?: object, execution?: string): Promise<void>
+        function activateFlowTriggerById(flowId: string, triggerId: string, data?: object, execution?: Execution): Promise<void>
     }
 
     /**
diff --git a/src/automations/index.js b/src/automations/index.js
index fedf47cc..6437dff8 100644
--- a/src/automations/index.js
+++ b/src/automations/index.js
@@ -74,7 +74,7 @@ export default class Automations {
     if (execution !== undefined && (typeof execution !== 'string' || !execution)) {
       throw new Error(
         // eslint-disable-next-line
-        'The "execution" argument must be a non-empty string and must be one of this values: "activateAny", "activateAll" or executionId.'
+        'The "execution" argument must be a non-empty string and must be one of this values: "activateAny", "activateAll" or Execution ID.'
       )
     }
 
diff --git a/test/unit/specs/automations/basic.js b/test/unit/specs/automations/basic.js
index 4292a7f3..cb05d039 100644
--- a/test/unit/specs/automations/basic.js
+++ b/test/unit/specs/automations/basic.js
@@ -299,7 +299,7 @@ describe('<Automations> Basic', function() {
 
     it('fails when execution id is invalid', async () => {
       // eslint-disable-next-line
-      const errorMsg = 'The "execution" argument must be a non-empty string and must be one of this values: "activateAny", "activateAll" or executionId.'
+      const errorMsg = 'The "execution" argument must be a non-empty string and must be one of this values: "activateAny", "activateAll" or Execution ID.'
 
       await expect(Backendless.Automations.activateFlowTriggerById(FLOW_ID, TRIGGER_ID, {}, null)).to.eventually.be.rejectedWith(errorMsg)
       await expect(Backendless.Automations.activateFlowTriggerById(FLOW_ID, TRIGGER_ID, {}, true)).to.eventually.be.rejectedWith(errorMsg)