diff --git a/.gitlab-ci-docs.yml b/.gitlab-ci-docs.yml
index bb0617f8a0653963084453fa92d3ce1ca35eab42..2f5d354c439b9771161fbd67587953788c1af5f0 100644
--- a/.gitlab-ci-docs.yml
+++ b/.gitlab-ci-docs.yml
@@ -6,13 +6,13 @@ docs:
 
   before_script:
     - apt-get update
-    - apt-get install -y --no-install-recommends gcc
+    - apt-get install -y --no-install-recommends gcc git
 
     # TODO: we should consider also version locking these packages:
     #  ++ everything will work in the future
     #  -- we won't see any future improvements of the mkdocs and mkdocs-material packages
     - pip install mkdocs
-    - pip install mkdocs-material
+    - pip install mkdocs-material mkdocs-minify-plugin mkdocs-git-revision-date-localized-plugin
 
     # This is my own extension that we use to insert the $VERSION env variable into the documentation
     - pip install pymdown-env
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b3361deafd5cc98b37e17a7f0e5649ec2b13ecaf..18a0352759cb91b9e22d95da2e98123df1c7ba65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+### v0.9.15 <small>_June 16, 2020_</small>
+* Server: Fixed chat
+* Server: Fixed `volume=0` not working
+* CI: Fixed build
+* Docs: Upgraded mkdocs-material
+
 ### v0.9.14 <small>_January 3, 2020_</small>
 * Server: Fixed channelsToIDCache not being initialized
 
diff --git a/docs/about/authors-notes.md b/docs/about/authors-notes.md
index 73037ba4be0517413a401af383be256942409f21..7867e352444323d9ec6f4bfb91ec7e8ed0dec044 100644
--- a/docs/about/authors-notes.md
+++ b/docs/about/authors-notes.md
@@ -5,4 +5,3 @@
 * <simon.kirsten@stud.h-da.de>
 * <https://github.com/skirsten>
 * `Simon#2307` on Discord
-* `simon.kirsten@stud.h-da.de` on Slack
\ No newline at end of file
diff --git a/docs/about/contributing.md b/docs/about/contributing.md
index 924bda09a20971c4e5df91d38e7da5b9158f989c..a6642b5d5bf8eef7ae8b583a3e605fd74e9bc578 100644
--- a/docs/about/contributing.md
+++ b/docs/about/contributing.md
@@ -25,16 +25,18 @@ The Stream Server is written in [Go](https://golang.org). It uses [Go Modules](h
 The `cmd/` directory contains only the `stream-server` command. The code of the server is in `internal/server` and the static files for the playback website in `internal/static`.  
 `pkg/` contains project independent code to access the Twitch API. This separation is done in accordance to the [Standard Go Project Layout](https://github.com/golang-standards/project-layout).
 
-Local development (requires go 1.12 and a Twitch client id):
-
-``` bash tab="bash" linenums="1"
-env TWITCH_CLIENT_ID="your client id here" go run ./cmd/stream-server
-```
-
-``` PowerShell tab="PowerShell" linenums="1"
-$env:TWITCH_CLIENT_ID="your client id here"
-go run .\cmd\stream-server
-```
+Local development (requires go 1.13 and a Twitch client id):
+
+=== "bash"
+    ``` bash linenums="1"
+    env TWITCH_CLIENT_ID="your client id here" go run ./cmd/stream-server
+    ```
+
+=== "PowerShell"
+    ``` PowerShell linenums="1"
+    $env:TWITCH_CLIENT_ID="your client id here"
+    go run .\cmd\stream-server
+    ```
 
 CI pipeline: `.gitlab-ci-server.yml`
 
diff --git a/docs/download-and-run.md b/docs/download-and-run.md
index bdec0045a33f5b48000457d1399810ad76fe51e5..72e78926ae7049201503c1ad04c5766e53dcdd92 100644
--- a/docs/download-and-run.md
+++ b/docs/download-and-run.md
@@ -2,7 +2,7 @@
 
 ## Download
 
-Version `~~~${VERSION}~~~`
+Version `~~~${VERSION}~~~` [changelog](about/changelog.md)
 
 OS              | CPU Platform  | Download
 --------------- | ------------- | ----------------------------------------------------------------------
diff --git a/internal/static/main.js b/internal/static/main.js
index f424df9f44cf22cf930ab96bb11bf4ee89274266..d9263cca6c1f63554a23d0e9b104a50a54630ced 100644
--- a/internal/static/main.js
+++ b/internal/static/main.js
@@ -56,7 +56,10 @@ function updateState(newState) {
   if (state.large_channel != "") {
     function update() {
       // the volume needs to be changed
-      if (large_player.getVolume() != state.volume) {
+      if (state.volume == 0) {
+        large_player.setMuted(true);
+      } else {
+        large_player.setMuted(false);
         large_player.setVolume(state.volume);
       }
 
diff --git a/mkdocs.yml b/mkdocs.yml
index c7c0c077859462840a092a026365a5e79878dc4b..c407b9a03e2d5c3f848c8c945534d6fbffc8255e 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -12,23 +12,26 @@ repo_url: https://code.fbi.h-da.de/stream-server/stream-server
 
 # Configuration
 theme:
-  name: 'material'
+  name: "material"
   language: en
-  # palette:
-  #   primary: 'blue grey'
-  #   accent: 'light blue grey'
-  feature:
-    tabs: true
+  palette:
+    scheme: slate
+    primary: lime
+    accent: lime
+  icon:
+    repo: fontawesome/brands/gitlab
+  features:
+    - instant
 
 # Plugins
 plugins:
   - search
+  - git-revision-date-localized
   - minify:
       minify_html: true
 
 # Customization
-extra:
-  repo_icon: gitlab
+# extra:
 
 # Extensions
 markdown_extensions:
@@ -57,21 +60,22 @@ markdown_extensions:
   - pymdownx.tasklist:
       custom_checkbox: true
   - pymdownx.tilde
+  - pymdownx.tabbed
   - pymdown_env
 
 # Page tree
 nav:
   - Stream Server:
-    - Project: index.md
-    - Download and Run: download-and-run.md
-    - Options: options.md
-    - Quickstart: quickstart.md
-    - Reference: reference.md
-    - Android Integration: android-integration.md
+      - Project: index.md
+      - Download and Run: download-and-run.md
+      - Options: options.md
+      - Quickstart: quickstart.md
+      - Reference: reference.md
+      - Android Integration: android-integration.md
 
   - About:
-    - Changelog: about/changelog.md
-    - Contributing: about/contributing.md
-    - Author's Notes: about/authors-notes.md
-    - Previous Considerations: about/previous-considerations.md
-    - License: about/license.md
+      - Changelog: about/changelog.md
+      - Contributing: about/contributing.md
+      - Author's Notes: about/authors-notes.md
+      - Previous Considerations: about/previous-considerations.md
+      - License: about/license.md