For what it's worth, version 5.11 of ExifMeta works for me in LR6. You get the nag message about it maybe not working, but so far it seems to.
Did you have to change anything with configuration or the file location of the plugin? I'm still having this problem since moving to Lightroom CC(6).
-sd
What problem are you having? As long as the website is offline, you won't be able to update the plugin. All I'm saying is that the current version of ExifMeta appears to work fine in LR6.
Because LR6 creates a new catalog, I found I had to save metadata to an image file to get the fields to appear in the field list in the plugin, but once I did that, it worked as it did in LR5.
