If there's any risk of stored data becoming unavailable or corrupted then you could play the DSM is no longer supported for security updates on these really old devices. [note: I haven't checked if this is true or not, chances are that the CFO won't too].
She's not a CTO, so that won't ring any bells to her. CFOs are usually pragmatic to evaluate immediate risks
So, even if this is true my device will soon be excluded from next security updates, I should not run into data loss. She never said anything when I had to replace any faulty (and expensive) 6Tb hard drives
Play on the benefits of upgrading to get features that aren't for you but will really help someone/thing the CFO has protective feelings to [not you, unless you're lucky!]. This one worked for me to get the
DS1520+ as I needed more space and oomph to use AB4B to backup the offsprings' laptops. I'm still getting around to re-purpose the
DS218+ to whatever I decide to do with it.
This is usually her way of thinking. As many non-IT person (whatever the gender), a new item will replace the old one. This is where they miss our point, the new one is the new flagship, does everything, works perfectly. The old one is repurposed in the homelab, offsite backup, "arousing materials", you name it. But it may sits for a while on the desk, and I already hear "weren't you supposed to get rid/sell the old one ?"
Get a lot of household deliveries in similar size boxes and then sneak in a new NAS.
ahah good idea ! my concern is that I don't have a dedicated space for that. For the moment it is placed on my desk in the living room. Going from a 1010 to a 1821 will get noticed at some point for sure.
Buy it and admit afterwards. Also a card I've played, and survived, though I did phone up from work to admit my guilt.
I did play this one once too, and survived, but I know I faced death, and I'm not sure I'm willing to experience it once again

Background story is she needed a new iphone for her birthday, but a cheap one because "you don't put 500€ in a new phone that's insane". while surfing the store website I saw a very interesting package for an xbox one. Bought it and stashed it in the basement until the date.
She had mixed feelings when I told her about the phone AND the xbox. But luckily I survived !
Thank you and
@jeyare for the advices, will open a bottle and see what would best work
