diff --git a/README-zh-cn.md b/README-zh-cn.md
index 1b0aef8..e1908f9 100644
--- a/README-zh-cn.md
+++ b/README-zh-cn.md
@@ -50,13 +50,6 @@ $ make build
 
 笔者时间和水平有限，如果读者发现书中内容的错误，欢迎提 [Issue](https://github.com/changkun/modern-cpp-tutorial/issues)，或者直接提 [Pull request](https://github.com/changkun/modern-cpp-tutorial/pulls)。详细贡献指南请参考[如何参与贡献](CONTRIBUTING.md)，由衷感谢每一位指出本书中出现错误的读者，包括但不限于 [Contributors](https://github.com/changkun/modern-cpp-tutorial/graphs/contributors)。
 
-<p>本项目还由以下产品提供赞助支持：</p>
-<p>
-  <a href="https://www.digitalocean.com/?refcode=834a3bbc951b&utm_campaign=Referral_Invite&utm_medium=Referral_Program&utm_source=CopyPaste">
-    <img src="https://opensource.nyc3.cdn.digitaloceanspaces.com/attribution/assets/SVG/DO_Logo_horizontal_blue.svg" width="201px">
-  </a>
-</p>
-
 ## 许可
 
 <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/"><img alt="知识共享许可协议" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-nd/4.0/80x15.png" /></a>
diff --git a/README.md b/README.md
index 537b6ad..afbac08 100644
--- a/README.md
+++ b/README.md
@@ -56,13 +56,6 @@ The author has limited time and language skills. If readers find any mistakes in
 
 The author is grateful to all contributors, including but not limited to [Contributors](https://github.com/changkun/modern-cpp-tutorial/graphs/contributors).
 
-<p>This project is also supported by:</p>
-<p>
-  <a href="https://www.digitalocean.com/?refcode=834a3bbc951b&utm_campaign=Referral_Invite&utm_medium=Referral_Program&utm_source=CopyPaste">
-    <img src="https://opensource.nyc3.cdn.digitaloceanspaces.com/attribution/assets/SVG/DO_Logo_horizontal_blue.svg" width="201px">
-  </a>
-</p>
-
 ## Licenses
 
 <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-nd/4.0/88x31.png" /></a><br />This work was written by [Ou Changkun](https://changkun.de) and licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License</a>. The code of this repository is open sourced under the [MIT license](./LICENSE).
diff --git a/website/src/modern-cpp/about/ack.md b/website/src/modern-cpp/about/ack.md
index 1e3107b..5d6f17e 100644
--- a/website/src/modern-cpp/about/ack.md
+++ b/website/src/modern-cpp/about/ack.md
@@ -12,20 +12,6 @@ The author has limited time and language skills. If readers find any mistakes in
 
 The author is grateful to all contributors, including but not limited to [Contributors](https://github.com/changkun/modern-cpp-tutorial/graphs/contributors).
 
-<p>This project is also supported by:</p>
-<p>
-  <a href="https://www.digitalocean.com/?refcode=834a3bbc951b&utm_campaign=Referral_Invite&utm_medium=Referral_Program&utm_source=CopyPaste">
-    <img src="https://opensource.nyc3.cdn.digitaloceanspaces.com/attribution/assets/SVG/DO_Logo_horizontal_blue.svg" width="201px">
-  </a>
-</p>
-
 ## 致谢
 
 笔者时间和水平有限，如果读者发现书中内容的错误，欢迎提 [Issue](https://github.com/changkun/modern-cpp-tutorial/issues)，或者直接提 [Pull request](https://github.com/changkun/modern-cpp-tutorial/pulls)。详细贡献指南请参考[如何参与贡献](CONTRIBUTING.md)，由衷感谢每一位指出本书中出现错误的读者，包括但不限于 [Contributors](https://github.com/changkun/modern-cpp-tutorial/graphs/contributors)。
-
-<p>本项目还由以下产品提供赞助支持：</p>
-<p>
-  <a href="https://www.digitalocean.com/?refcode=834a3bbc951b&utm_campaign=Referral_Invite&utm_medium=Referral_Program&utm_source=CopyPaste">
-    <img src="https://opensource.nyc3.cdn.digitaloceanspaces.com/attribution/assets/SVG/DO_Logo_horizontal_blue.svg" width="201px">
-  </a>
-</p>
\ No newline at end of file