Override the compile target adding a line that deletes the existing pod before recompiling.

Example below. the override code should work for standard F4 Fantom projects and needs to be added to your own build pod script.

Edited to make the delete command more general as below.

using build
class Build : build::BuildPod
{
  new make()
  {
    podName = "projadmgui"
    summary = ""
    srcDirs = [`fan/`]
    depends = ["sys 1.0", "gfx 1.0+", "fwt 1.0+", "concurrent 1.0+", 
               "fluxText 1.0+", "sql 1.0+"]
  }
  
  @Target{help = "Delete target and recompile"}
  override Void compile()
  {
    outPodDir.plusName("${podName}.pod").toFile.delete
    super.compile
  }
}

Cool.

Use a URI literal and Fantom interpolation to abbreviate the line a bit:

`bin/fan/lib/fan/${podName}.pod`.toFile.delete

How about this?

Should use outPodDir it is more general:

outPodDir.plusName("${podName}.pod").toFile.delete