Corpsewade sockets

I have several pairs of corpsewade iron greaves that go all the way up to level 19 decompose skill. I just hit level 90 and was told by someone that's when i get my 5th socket but i still only have 4. What do you need to do to get the fifth Socket?

Brian

That's strange, because as I leveled my character, I got more sockets on decompose. Does that mean that it can never get the fifth socket?

There is no corpsewade boots with level 20 decompose on the server as far as we know.
The most "seems like it" assumption is that we need lv 90 item since lv 20 skills require lv 90.

"

that's when i get my 5th socket

For example, the level of default attack skills on player character increase as the character levels up. Currently this seems an exception.
All other skills need to be leveled via uncut skill gem (which does not work on item skills) or corrupting (which does not affect the item skills).

"

That's strange, because as I leveled my character, I got more sockets on decompose. Does that mean that it can never get the fifth socket?

That seems not true. You can check with different skill levels on corpsewade. It requires certain level to have more sockets. (Not the total level but the level from gem.)