diff --git a/.unicornfig.yml b/.unicornfig.yml
index bd2ae77..94648f6 100644
--- a/.unicornfig.yml
+++ b/.unicornfig.yml
@@ -7,5 +7,5 @@ description: "This repository contains the original interface definitions of pub
   \ definitions can provide a better understanding of HPI Cloud APIs and help you\
   \ to utilize them more efficiently. You can also use these definitions with open\
   \ source tools to generate client libraries, documentation, and other artifacts."
-version: "0.0.10"
+version: "0.0.11"
 githubName: "HPI-de/hpi-cloud-apis"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e204e52..9091748 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+## [0.0.11] - 2019-10-06
+### BREAKING CHANGES
+- **course:** add Course.attendance, enrollment_deadline; make CourseSeries.mandatory an enum
 
 ## [0.0.10] - 2019-10-05
 ### BREAKING CHANGES
@@ -91,7 +94,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 Initial release with NewsService.
 
 
-[Unreleased]: https://github.com/HPI-de/hpi-cloud-apis/compare/0.0.10...dev
+[Unreleased]: https://github.com/HPI-de/hpi-cloud-apis/compare/0.0.11...dev
+[0.0.11]: https://github.com/HPI-de/hpi-cloud-apis/compare/0.0.10...0.0.11
 [0.0.10]: https://github.com/HPI-de/hpi-cloud-apis/compare/0.0.9...0.0.10
 [0.0.9]: https://github.com/HPI-de/hpi-cloud-apis/compare/0.0.8...0.0.9
 [0.0.8]: https://github.com/HPI-de/hpi-cloud-apis/compare/0.0.7...0.0.8
diff --git a/build.gradle b/build.gradle
index 3a436e5..2615ffe 100644
--- a/build.gradle
+++ b/build.gradle
@@ -35,7 +35,7 @@ ext {
     githubReleaseNotes = 'CHANGELOG.md'
     allLicenses = ["Apache-2.0"]
 
-    libraryVersion = "0.0.10"
+    libraryVersion = "0.0.11"
 }
 
 task sourcesJar(type: Jar, dependsOn: classes) {
diff --git a/hpi/cloud/course/v1test/course.proto b/hpi/cloud/course/v1test/course.proto
index 8fe8a9d..ebf3732 100644
--- a/hpi/cloud/course/v1test/course.proto
+++ b/hpi/cloud/course/v1test/course.proto
@@ -2,6 +2,9 @@ syntax = "proto3";
 
 package hpi.cloud.course.v1test;
 
+import "google/protobuf/wrappers.proto";
+import "google/type/date.proto";
+
 option java_multiple_files = true;
 option java_outer_classname = "CourseProto";
 option java_package = "de.hpi.cloud.course.v1test";
@@ -28,8 +31,14 @@ message CourseSeries {
   // Required. The hours per week that courses of this series typically require.
   sint32 hours_per_week = 6;
 
-  // Required. Whether it's mandatory to particiapte in a course of this series.
-  bool mandatory = 7;
+  enum Compulsory {
+    NON_COMPULSORY = 0;
+    COMPULSORY = 1;
+    BRIDGE = 2;
+  }
+
+  // Required. Whether it's mandatory to participate in a course of this series.
+  Compulsory compulsory = 7;
 
   // Required. The language courses of this series are taught in. Must be a valid [BCP 47](https://en.wikipedia.org/wiki/IETF_language_tag) language tag.
   string language = 8;
@@ -39,6 +48,7 @@ message CourseSeries {
     SEMINAR = 1;
     BLOCK_SEMINAR = 2;
     EXERCISE = 3;
+    PROJECT = 4;
   }
 
   // Types of this course series. Must contain at least one value.
@@ -81,6 +91,12 @@ message Course {
 
   // A website that contains more information about the course.
   string website = 6;
+
+  // An optional upper bound for the number of participants.
+  google.protobuf.UInt32Value attendance = 7;
+
+  // The enrollment deadline.
+  google.type.Date enrollment_deadline = 8;
 }
 
 // Details of a course.