I want to rearrange the order of a manga series

You can change the order of a manga series from the desktop and mobile versions of pixiv.
It cannot be done from the app.
The procedures are as follows:

＜On desktop＞

1. Please click the pen mark next to the title and thumbnail of the manga series.
   
   
2.  If you click "View all" to the left of the work, you'll open the "Works in this series" menu. You can change the order of the works by dragging and dropping the ≡ symbol to the right of the works.
   * The topmost work will be the most recent episode.
   
   
3. Once you've decided on the order of the manga series, you'll be able to change it by clicking "Confirm" and then "Save changes".

＜On mobile＞

1. Please tap the pen mark next to the title and thumbnail of the manga series.
   
   
2.  If you tap the "View all" button to the left of the work, you can open the "Works in this series" menu.
   
   
   
   
3. You can change the order of the works by dragging and dropping the ≡ symbol to the right of the works.
   * The topmost work will be the most recent episode.
   
   
   
   
4. Once you've decided on the order of the manga series, you'll be able to change it by clicking "Confirm" and then "Save changes".