Compiling for old version

I want to compile a map for an old version of CSS. I can’t use the normal bsp, because that’s bsp version 20, and I need bsp version 19. Does anyone know how I could do this? (I need it to run on a portable version of CSS so I can use it at a LAN party, also, I have the vmf, I made the map myself, ALSO for you moralfags, I do own CSS).

Why do you wish to use it for an old version of CSS?

Use the compile tools from…
Wait, the SDK base didn’t come with it’s own mapping format, did it?
I dunno.

Download a new portable version.

Well generally, as far as I’m aware, it will optimize should I say, old maps to update them, but why roll-back to an older version? there’s no need. I’m not sure.

I have an idea, go back in time and download the SDK running bsp v19

As far as I can tell, the only difference between v19 and v20 BSPs is that v20 has additional lumps to specify HDR data. That in mind (and obviously back up first), changing the 5th byte (the first four are the VBSP header) of the file from 14h to 13h using a hex editor SHOULD in theory work.

It accepts the file and starts to load, but then crashes with the error

That’s actually what I wanted to do(without the time-travel part), any idea where I could find an old version?

Yeah, upon further reading, the leaf structure has changed from v19 to v20. That’s not going to be fixable at all. Sorry, https://www.bagthorpe.org/bob/cofrdrbob/bspformat.html is a long document and I missed that alteration.

have you tried torrents?

Yep, couldn’t really find anything.

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