With the release of PDF Expert 5, Readdle moved away from heavy textures to a clean, flat design. This update introduced the signature red navigation bar feel into the icon itself, emphasizing the "document-centric" focus of the app.

The icon has undergone several major transformations to stay "razor sharp" on evolving displays:

Readdle has consistently aimed for a balance between . The icon's primary goal is to provide a "visual cue" that immediately identifies the file type and the professional grade of the tool.

Often depicts a stylized piece of paper or a folder, signifying the app’s roots in file management and organization.