There is something called standard work, but

I was upgrading macports and ruby installation on my mac when I noticed that git stopped working. Every time I ran a git command I got the error below:

dyld: Library not loaded: /opt/local/lib/libiconv.2.dylib
Referenced from: /opt/local/bin/git
Reason: Incompatible library version: git requires version 8.0.0 or later, but libiconv.2.dylib provides version 7.0.0

I checked the libiconv.2.dylib,

> otool-L / opt/local/lib/libiconv.2.dylib
/opt/local/lib/libiconv.2.dylib:
/opt/local/lib/libiconv.2.dylib (compatibility version 8.0.0, current version 8.0.0)
/usr/lib/lib System.B.dylib (compatibility version 1.0.0, current version 125.0.1)

I struggled for hours trying to fix this issue, but was at a loss. Then I viewed already installed libiconv:
> sudo port installed libiconv
The following ports are currently installed:
libiconv@1.13_0
libiconv@1.13.1_0 (active)

I tried switching back to the older version
> sudo port activate libiconv@1.13_0

And voila, the switch resolved the issue. Hope this helps people that encounter this.