[Plugin: KB Advanced RSS Widget] Problems with characters

That’s, usually, not a problem on your end: it is because the feeds you are displaying have different encoding than your blog.

So, how can I fix this?
Any suggestion?

There is nothing really you can “fix”. Until the whole web will use utf-8 – that will fix it automatically.

Ok, but if I change into UTF-8 in OPTIONS, they appear another strange characters, so I think that UTF-8 is not correct codification for spanish language.

I don’t really care what you think… because I know that utf-8 is universal and it works with all languages.

Is your blog set to utf-8? That’s the default if you don’t mess with it.

Same issue going on here. Both feed and blog are checked to be UTF-8 yet some characters, most notable ‘ display questionmarks. What gives?

Turns out that Polyglot (multi-language plugin) offers a setting for localizing RSS-feeds. Once set the problem was solved.