The Video Watchdog article claims that there are seven different versions.
Hampton Fancher did several drafts of the screenplay. These drafts concluded with Deckard taking Rachael out of the city, letting her see nature for the first time, and then, because she doesn't want to be caught by the police, shooting her in the snow. David Peoples was brought in to polish the script, and Ridley Scott asked him to include more detective work. Peoples worked on the humanity of Deckard's adversaries. His daughter mentioned the biological term "replicate", which led to "replicant". Peoples also told Scott that the screenplay was virtually perfect before he worked on it.
Some of the scripts are available.
The rumours of a three-hour version of Blade Runner are just that: rumours. No version of the script could be made into a film of that length. Mary was cut before any of her scenes were filmed.
There are some scenes that were filmed but cut and not included in any version.