upgrading to php5

[Chris]

What scripts can I expect to break (this server was just upgraded).

[Selkirk]

I assumed you've gone to 5.2.x. The big things seem to be php.ini settings and reference handling (http://www.php.net/manual/en/migration51.references.php) changes. I've run into a variety of misc problems, such as changes in E_STRICT handling, changes in the order of execution of shutdown events, etc. Some documented, some not. For the most part, everything works.
Just give your apps a good work-through.

Migrating from PHP 4 to PHP 5.0 (http://www.php.net/manual/en/faq.migration5.php)
Migrating from PHP 5.0 to 5.1 (http://www.php.net/manual/en/migration51.php)
Migrating from PHP 5.1 to 5.2 (http://www.php.net/manual/en/migration52.php)

Thats for custom stuff.

Most packages like WordPress and vB have already had the kinks worked out. Just upgrade to the latest versions.

[Todd W]

What scripts can I expect to break (this server was just upgraded).

I actually didn't have any break! I was shocked, none of my custom stuff broke, and wordpress was fine as well as VBulletin, and other common apps.

I did have to tweak the security and application settings though in php.ini

-Todd

[Chris]

SO far nothing of mine has broken either. The only thing I needed to change was an include that was done like include("http://www......") to include("/home/site/public_html/folder")

[bbolte]

I've found that XML DOM stuff seems to be different from v4 to v5

[Todd W]

SO far nothing of mine has broken either. The only thing I needed to change was an include that was done like include("http://www......") to include("/home/site/public_html/folder")

I just changed the setting to allow remote includes, heh.