it came with Bitmainer version 2.0.0 and Hardware version 30.0.1.3. I was checking the lates version on Bitmainer however there is no reference of which version is which, like ver 2.0 or ver 2.1 etc. they just have Anminer-s9j-xilinx-2019073etc..
I wonder which version do I have to download or if the version I have is the lates version.
You are looking at the wrong data, you want to look for the file system version on the system> overview page, something like this
File System Version Wed Dec 25 09:47:07 CST 2019
Ideally, you can get the commit version from the kernel log (not available for all miners), or the build date which is available on all miners, here is an example of one of my gears
2021-07-11 22:08:46 driver-btm-api.c:1875:bitmain_soc_init: commit version: b1e11d0 2019-12-24 22:26:20, build by: lol 2019-12-25 09:59:19
If you go to their website, you will see the name of the firmware has a date in it, this is how they reference the versions they release, if you want the latest one you just download the one that has the most recent date, if it says 20201225 and yours is, for example, Wed Dec 25 09:47:07 CST 2019 then it's not the latest version.
Finally and most importantly you want to always avoid flashing the latest firmware unless you really have to, the latest versions does nothing more than making it more difficult to flash different firmware, if your miner is running anything 2018 or newer then it has Asicboost enabled, which is probably the only improvement bitmain did since the first firmware for the S9.