Honestly, at this point I, the need to update my 3DS is no longer necessary, since :
1. I only play SinglePlayer games
2. I only install games via cia, never download directly from CDN (via freeshop or similar)
3. As stated by the OP, using games prior to the update, that're installed via cia, can still work (offline and online).
So long as you stayed offline, or to the very least download games from "those" sites rather than directly from the CDN, I think yer good to go.
1. I only play SinglePlayer games
2. I only install games via cia, never download directly from CDN (via freeshop or similar)
3. As stated by the OP, using games prior to the update, that're installed via cia, can still work (offline and online).
So long as you stayed offline, or to the very least download games from "those" sites rather than directly from the CDN, I think yer good to go.