How the 1-click upgrade work?

[bsm]

I'm going to upgrade from PS 1.5.4.1 to 1.5.5.

From yesterday I'm getting lots of wornings in my 1.5.4.1 like:

 

Warning: preg_match() expects parameter 2 to be string, array given in /home/efunkyba/public_html/classes/Validate.php on line 177
 

Warning: Cannot modify header information - headers already sent by (output started at /home/efunkyba/public_html/classes/Validate.php:177) in /home/efunkyba/public_html/classes/Tools.php on line 141

 

Warning: include(/home/efunkyba/public_html/translations/en/pdf.php) : failed to open stream: No such file or directory in /home/efunkyba/public_html/classes/Translate.php on line 208

Warning: include() : Failed opening '/home/efunkyba/public_html/translations/en/pdf.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in/home/efunkyba/public_html/classes/Translate.php on line 208

 

and many more

there is not any errors in shop log.

 

My question is:

does 1-click upgrade override the files? will all this errors be corrected or not?

should I better upgrade manually?