Steps to reproduce:
Expected behavior: Installer should warn of the file integrity issue, but let you install anyway.
Actual behavior: Installer warns about file integrity issue, but offers no way to continue.
Tested using Piwik 2.13.1 and Piwiki 2.14-RC.
Linux server with PHP 2.4 (GoDaddy).
Viewed on Firefox 38.0.5, Windows 7.
This has regressed - let's try to fix it for 2.14.0