Alhamdulillah, my weblog already upgraded from BlogEngine 1.2 to BlogEngine.NET 1.4.5. Upgrading process is easy but should be carefully because there are incompatible settings and themes between BlogEngine 1.2 and BlogEngine 1.4.5. To upgrade BlogEngine from version 1.3 or 1.2 to version 1.4.x, you must prepare following items before upgrading:

1. Upgrade theme if you are using custom theme (not included in theme package).
2. Backup your xml data or database
3. Backup your settings
4. Create custom widget (if needed).

I’m alredy updated my theme (Cogitation) for BlogEngine 1.4.x and create new widget (Image List) for displays image in the side bar. You can download Cogitation theme and Image List widget from following links.

After upgrading BlogEngine, theme and installing widget, you might be need to reconfigure widgets. Rearange and add widget that you want to display in side bar.

I hope my theme and widget are useful for you.