Adobe does not host version 11.0.23 on its official website anymore. Attempting to download from third-party "old version" sites is a security minefield—many of those downloads are bundled with trojans. If you absolutely need the original, clean installer for archival purposes, refer to:
Isolate Reader XI 11.0.23 inside a Windows 7 virtual machine (VM) with no network access. Use a shared folder to transfer sanitized PDFs into the VM. This preserves the lightweight feel while creating a security buffer. adobe reader xi version 11.0.23
Version 11 placed a heavy emphasis on forms. It introduced improved auto-complete features for form fields and a simplified signing experience. Users could type, draw, or insert an image of their signature directly into documents without requiring a digital certificate infrastructure. This was a move to reduce the friction of paper-based workflows. Adobe does not host version 11