[skariks]

Hello all,

First I'd like to say a big "Thank you!" to the author and anyone who contributed to Calibre project for the great software!

In short I've got here while searching for a convenient way to upgrade Calibre from version 4.23 to the latest 5.5 on Windows 7. I wanted to post my findings in the thread "Windows 7 compatibility excessive restriction", but it seems closed, so I couldn't do that.

I'm sure there are still many people like me that for many reasons are staying on Win7 and in the same time want to use latest version of Calibre, which provides new features, fixes and etc.
I don't want to go into more details or discussions why I'm staying on Win7 or whatever, but just want to share the workaround I've found for myself and that it works excellent for me, so if someone else wants to try on his own risk - below is the best solution for me.

I'm not sure that I can post here any links to external sources, so I'll describe the way I've installed Calibre 5.5 64 bit edition MSI installer on my Win7.

There is a MS tool called Orca, which allows editing of MSI installers and it is part of Microsoft Windows Software Development Kit (SDK). It is available from MS and free to download on their site - just search for it.
I've used currently the latest version Windows 10 SDK (10.0.19041.0) and downloaded the .ISO package, so that I can install only Orca from in it.
You should mount the .ISO file or open it with 7-Zip and extract the whole "Installers" sub-directory somewhere on your computer and then install Orca-x86_en-us.msi.
It will install silently without any popup windows or setup wizards and will integrate in Windows Explorer Context Menu (Right click menu on a file).
After you have Orca installed already download the Calibre 5.x installer version you want and select it, right click on the file and choose "Edit with Orca" from the menu.
In the newly opened window of Orca located in the left pane titled "Tables" the row "LaunchCondition" and select it. On the right pane you will see a grid with 2 columns "Condition" and "Description".
Select the "Condition" column and double-click on the only row with text "Installed OR (VersionNT >= 602)" and you will enter in edit mode in the cell. Change the version required from 602 to 601, so that the text in the condition cell is "Installed OR (VersionNT >= 601)".
That's all and you are ready. Hit enter and to exit edit mode, close the Orca app and confirm saving the changes on exit.
Now you can install the Calibre 5.x using the install wizard without the blocking validation for Windows 8 and newer version. Note that the value of 601 means Windows 7 in condition validation ("Installed OR (VersionNT >= 601)").

For me Calibre 5.5 64 bit works excellent and books are displayed as it should in the Viewer (when I select "View" button in the toolbar). For me it is working the same way on v3.x, v4.x and now v5.x.

I hope that by providing this workaround anyone could try it on his own risk and if something goes wrong - doesn't blame or ask for help the author/developer of the Calibre, as it is clearly stated that Win7 is not officially supported for v4.x and newer!


Regards