I did both ways on 2 different domains, and upgrading was just fine, if you use and really use a lot of plugins and hacks, don't forget to backup all your skins before doing so.

Also you might want to erase all b2evolution files before uploading a fresh install of the 2.0.2 version to then upgrade the DB. so you don't have old files in the middle of the new ones. (my point of view)

Upgrading will be just fine, you just need to know that if you upgrade to 2.0.2, you won't be able to revert back to 1.X if in the middle of the journey, you change your mind.

For me going to 2.0.2 was a "must do".
only think the bonus you get by using this version, you'll see that it's worth the work.

there are 2 things that really make this version a blast :

Widgets and the new skin system. 10/10

SEO : you can define the way URL's are created on your blog, then define search engine friendly words for your blogs name and category name; no more cat=156 wich mean nothing to search engine. 10/10

Also the new admin skin, everything is better.
i just love the toolbar when logged, it makes you blog more often and more easely, very well done :)

can you tell me what are those b2evolution files that need to be erased? i dont have any idea. which ones should be retained? which is which?

thanks for your reply.

well it is simple.. where is your blog located ?
yoursite.com/myblog or is it on the root of the server ? like yoursite.com (wich is your blog? )

in both case you can erase everything in the blog folder, don't worry your content is not in static files.

first backup everything. then if you don't want your website to appear like a big mess, create a simple "in construction page" named index.php put it on the root of your server or where your blog was located yoursite.com/blog

after that :

what is to be retained is in your /yoursite.com/blog/conf/ folder named basic_config.php (this file have all the info concerning your DB also your skin folder or any php file you know you hacked at some point.

when everything is erased, upload everything back from the 2.0.2 version. i suggest your to use first one of the skin that comes with the default installations, you will choose your final skin later on.

then upload your basic_config.php back to your yoursite.com/blog/conf/ or yoursite.com/conf folder then head to yoursite.com/blog/install/

choose upgrade from another version, follow the steps on your screen, then loggin, your upgrade is done and you can be sure all the files in your server belong all to the latest b2evolution version.

you might only need to do this things (erasing old files) this time because we are changing from 1.X series to 2.X - next upgrade, you will only need to overwrite existing files.

I hope it help.

ps: if you don't erase the old files, don't worry, your upgrade will still work like a charm but you might have some old files, here and there..