items.yml:

items-Version: 8
items-Delay: 2
items-Overwrite: true
items-Spamming: false
items-RestrictCount: false
items:
  map-item:
    id: FILLED_MAP
    map-id: 3
    slot: 3
    name: '&eNews'
    lore:
      - '&7Any good news today?'
    itemflags: inventory-modify, unbreakable, hide-attributes, death-drops, self-drops, creativebypass
    triggers: join, respawn, world-change
    permission-node: 'itemjoin.map'
    enabled-worlds: world

I get the following error:

[18:31:10] [Server thread/INFO]: [ItemJoin] Configuration(s) Reloaded!
[18:31:11] [Server thread/ERROR]: [ItemJoin_ERROR] {ItemDesigner} The Item map-item's Material 'ID' is invalid or does not exist.
[18:31:11] [Craft Scheduler Thread - 59/INFO]: [ItemJoin] Hooked into { WorldGuard, Citizens, Vault }
[18:31:11] [Server thread/WARN]: [ItemJoin_WARN] {ItemDesigner} The Item map-item will not be set!
[18:31:11] [Craft Scheduler Thread - 59/INFO]: [ItemJoin] 5 Custom item(s) loaded!

And as I previously used (on old ItemJoin version) ID: MAP, it just creates a new map (not setting the correct map-id)

Paper version git-Paper-1618 (MC: 1.12.2) (Implementing API version 1.12.2-R0.1-SNAPSHOT)

So FILLED_MAP is 1.13+ whereas MAP is for versions below 1.13 aka 1.12.2. -- not my choice, Mojang just simply renamed MAP to FILLED_MAP in 1.13.

I would need some additional info to figure out why it wouldn't be working for you, can you provide the output when you type /itemjoin so I can test the exact build number?

So FILLED_MAP is 1.13+ whereas MAP is for versions below 1.13 aka 1.12.2. -- not my choice, Mojang just simply renamed MAP to FILLED_MAP in 1.13.

I would need some additional info to figure out why it wouldn't be working for you, can you provide the output when you type /itemjoin so I can test the exact build number?

ItemJoin v5.2.4-RELEASE-b822 by RockinChaos

I previously used version 4.4, and it worked on there but I'm now trying to update to the latest because the newer the better, usually

Hmmmm so after checking it seems that the map id is being properly set.
Could you send me your player.dat file (get the item then log off the server) so I can inspect it with my nbt editor to confirm if the mapid is set or not.

This is using snapshot b847.
https://ci.craftationgaming.com/job/ItemJoin/

Using ItemJoin v5.2.5-RELEASE-b850
(Tested with b847 but didn't make any difference for me :()

Uploading 79e21065-394d-4e73-ab7d-a21d13763be6.dat…
itemjoin_test_b850.zip

Apologies for the late update on this, it took a while to figure this issue out.

A recode was done on the maps to better reflect the original functionality of v4.4.
I have tested it and it seems to work perfectly now on MC 1.12.2 in conjunction with other mapping plugins.

Simply just set the matching map-id and the renderer will automatically be handled.

Link; https://ci.craftationgaming.com/view/Chaos/job/ItemJoin/875/
Remember to remove your old ItemJoin.jar file

Let me know!~