Use "opkg update" in old versions

I have an old modem on which openwrt is installed, I have customized its version :

BusyBox v1.19.4 (2017-07-19 17:06:54 CST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 BARRIER BREAKER (Bleeding Edge, unknown)
  * 1/2 oz Galliano         Pour all ingredients into
  * 4 oz cold Coffee        an irish coffee mug filled
  * 1 1/2 oz Dark Rum       with crushed ice. Stir.
  * 2 tsp. Creme de Cacao

When I use the "opkg update" command, I get the following error, what can I do?

root@CPE:~# opkg update
wget: not an http or ftp url:
Collected errors:
 * opkg_download: Failed to download, wget returned 1.

What is the device?

ubus call system board 

you have your own openwrt setup, and you're asking us why it isn't working ?

error :
root@CPE:~# ubus call system board
Command failed: Not found

This version is now on my modem and I want to install new packages, but I can't

then you are not running a standard Openwrt

could you kindly provide the router name and its specific version

you're not answering the question.

and you probably won't be able to.

The fact that it says "BARRIER BREAKER (Bleeding Edge, unknown)" does not indicate which version was used?

yes, and it's 10 years old.

Can I update to the latest version?

how can we tell, we know nothing about your device.

the manufacturer of this modem/router may have modified the source code of the version you see installed at this moment a little or a lot.

This is why I'm asking you the specific brand and model. Without this information I can't even know if your device is supported or not by the current Openwrt

cat /proc/cpuinfo
system type             : SQNASIC rev 0
machine                 : Generic SQN board
processor               : 0
cpu model               : MIPS 24KEc V5.5
BogoMIPS                : 244.53
wait instruction        : yes
microsecond timers      : yes
tlb_entries             : 64
extra interrupt vector  : yes
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0090, 0x0bb8, 0x0b10, 0x0748]
ASEs implemented        : mips16 dsp
shadow register sets    : 1
kscratch registers      : 0
core                    : 1
VCED exceptions         : not available
VCEI exceptions         : not available

post free and cat /proc/mtd output too.

             total         used         free       shared      buffers
Mem:         37936        26176        11760            0          796
-/+ buffers:              25380        12556
Swap:            0            0            0
cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 02000000 00010000 "spi0.0"
mtd1: 000c0000 00010000 "Bootrom"
mtd2: 00040000 00010000 "Usim"
mtd3: 00040000 00010000 "Kvs"
mtd4: 00040000 00010000 "Unused"
mtd5: 00a80000 00010000 "kernel"
mtd6: 01400000 00010000 "region_fs"
mtd7: 00a00000 00010000 "rootfs"
mtd8: 001b0000 00010000 "rootfs_data"
mtd9: 00a00000 00010000 "rootfs_next"

32mb RAM is a huge no go, if it was ever supported, it'd have been EOL:ed already.

openwrt wants at least 64mb RAM, today, and those devices are discouraged, going forward.

There has never been trunk/sqn repo.
Likely you are using some OEMs private build, without possibility to use the regular OpenWrt packages for that ancient version.