Past and present installers are always available under releases at the main code hosting location. The latest release will be on top. You can see what’s changed between releases by looking at the ChangeLog.
Note that PageEdit currently provides Windows installers for x86 and x64 and will only work on Windows 7 or newer. Mac OS X binaries are typically one version behind the current release. This means that today 10.10 is the current release so it should run on the 10.9 (with the latest updates installed). However, this is subject to change and this information is not always current. Especially for OS X. This is an at best support for older versions of Windows and OS X.
All releases also have CHECKSUM.sha256 file which includes sha256 check sums of the file posted. This will let you know if you have a bad download or if a build has been tampered with.