[stumped]

baffled by my own past actions!

some of my books have, in their content.opf, fields like
<meta content="London Steampunk" name="calibre:series" />
<meta content="2.0" name="calibre:series_index" />

so apps like calibre-sync will determine that the above is book 2 of a series

in some other books, it has been done this way:
<meta name="calibre:series" content="Rivers of London" />
<meta name="calibre:series_index" content="3.0" />

and in some books - no .opf series entries at all, even though there is series data in calibre

I can't remember or find instructions for how I was able to add this data to some but not all of my library. any clues, anyone please ?

[ unless its not something that I once did ]

[ i know that save to disc will do it, but I doubt that's what I did, as I'd then have to import the saved book back into calibre to update/overwrite the source book]

what tools or plugs ins are capable of adding the series into from calibre fields into the book opf?

i usually only use the modify epub plug in and that does not seem to be able to do it

i like to be consistent with all series metadata, as apps like calibre-sync will then be more reliable. I have been testign calibre syn on a dropbox copy of my library, and it will pass series info to device IF it finds any in the .opf, but not otherwise

I don't have a huge amount of series, so I would happily auto update all relevent books - one series at a time- if I knew how - but I don't want to manually edit each .opf