P53x11

I've had good results with this in my N54L: EnLabs PCIEU3ACS20 PCI-e to 4 Ports USB 3.1 GEN 1 (5Gbps) https://www.newegg.com/en-labs-model-pcieu3acs20/p/17Z-00FJ-00002?Item=9SIACJF7CU4192

One thing to consider, do you hibernate the drives? 6.2.3 isn't known to be reliable with hibernation, which is why I've kept my archive box on 6.1.7 but am using 6.2.3 for production data.

Your hardware is definitely capable and stable with both 6.1.7/1.02b and 6.2.3/1.03b versions/loaders as ds3615xs. See the excellent table linked below to help you make your choice. I've updated a baremetal HP N40L microserver with drives intact from 5.2 to 6.1.7 and 6.2.3. And make sure you've disabled C1E in the bios. If your drives are SHR, they are grandfathered and transition seamlessly. If you are doing a clean install and want SHR, you'll have to make some OS edits to allow it. The primary piece to remember when updating from 5.2 is deleting the ".xpenoboot" directory or your NIC won't work. Either way it makes sense to make a configuration backup in advance. And like everyone says, also have a full backup of your info for the just in case. There are a few synology plugins that work differently with 6.1.7 vs 6.2.3 [synology drive client, hyper backup, etc.] which are generally minor. For me the big decisionmaker was that drive hibernation isn't yet stable in 6.2.3, which means I've kept my "archive" machine on 6.1.7 while the primary is on 6.2.3.

6.1.7/6.2.3 each require a different loader [1.02b/1.03b respectively] which is also nicely summarized here. The features enabled/disabled with each configuration are helpful in your decision:

Any direction you go should be fine. Since this will be your "archive" machine, you may find it better to go with a completely fresh install, then if you like restore your previously saved configuration backup with usernames, networking, etc. I've had both 6.1.7 and 6.2.3 on my machines, both are great. One is the previous generation HP N40L, which works straight out of the install using 1.02b/1.03b respectively. If you want the hard drives to hibernate, that may be a reason to stay with 6.1.7 [unless there is new information about hibernation stability in 6.2.3]. If you do decide to roll your old installation forward, make sure you delete the old ".xpenoboot" folder, otherwise 6.2.3 will wreak havoc on your NIC. My upgrade path was 5.2 to 6.1.7 to 6.2.3, but that took a little more time.

- Outcome of the update: SUCCESSFUL - DSM version prior update: DSM 6.2.2-24922 Update 4 - Loader version and model: Jun's Loader v1.03b - DS3615xs - Using custom extra.lzma: YES - Installation type: BAREMETAL - HP Microserver N40L - Additional comments: Remember to delete ".xpnoboot" or your NIC won't work