Generally, should EE1 add-ons work in EE2?

EE 1 add-ons will not work with EE 2. They need to be converted.

In particular, I’m looking for support for Publish Plus.

FYI I asked Leevi directly about this add-on and he said at the time he planned to convert it as soon as possible. From what I gather it is in less demand than most of his more popular add-ons which is why an EE2 compatible version is not yet available.

Please understand this is second hand info and not official :p You may want to email him directly.

I just got a reply from Leevi. He said:

When the hooks become available I’ll port the adding over. Hopefully by the end of the year.