US Upgrading Heirlooms; Any negatives from a L19/L29 Twink Persepective?

[Mumps.Undead]

In the past, I remember a friend upgraded an heirloom to max level, 100, and when she did it interfered with her low level twink toons. I do not recall exactly how, but I do know she was unable to use them the way she wanted once she upgraded from 90. Maybe some of the old enchants wouldn't work on them, or she was unable to create one from her loom tab, or something similar?...I cannot remember.

Does anyone remember this? And, is this still a thing? I've kept all my heirlooms at L90 for years because of the fear of this happening.

Kinda wanting to up them all to 100 now - but not at the expense of my low levels. Anybody care to elaborate on or confirm this? Is it safe to up them all to L100 nowdays, without any adverse affects to my lowbies? Thanks in advance!

 

[Burg]

Doesn't even matter.

 

[Holythane]

Once they go to 100 you cant use the leatherworking enchants on them which are bis (outside of bgs) if you dont have Legion invasion gear.

 

[Leek]

I'm not sure what happens above 90 but for lower levels I don't see any problem.

 

[Allybeboba]

Many enchants will not work on gear that are ilvl 600+. The issue with this is if the toon that is enchanting your heirlooms is a higher level toon you will run into issues since those upgraded heirlooms will scale up to as high as 605. I have purposely kept a toon at level 85 because of this.

/cheers