What drives are supported in an EX4100? Can I use a 10TB drive?

The default is 6TB 5400 RPMs for the EX4100-24TB kit.

Looks like 32TB (4x8TB) is supported OOTB but not 40TB.
Are 10TB-Pro supported for this server?

There now seems to be a new series, the PR4100 that does appear to support 40TB (4x10TB).

I do not see anything specific in the specs for the EX4100 that would identify a restriction.
Are there any known issues putting a 10TBPro drive in an EX4100?

My Cloud EX4100 supports drives upto 24TB (4x6TB) storage while My Cloud PR4100 supports upto 40TB storage. There is no issues in My Cloud EX4100 but as per its specifications, EX4100 enclosure would be able to deliver power to drives upto 24TB storage for their operating performance. However, using drives with larger storage than supported, might lead to failure operation of EX4100. You may refer below link for further details about My Cloud EX4100:

I have already seen the product spec sheet. This one doesn’t even list the 32TB version that is available and WD support is horrible. They’ve stated that ONLY the standard 6TB (non-Pro) drives are support and it took them 19 days to complete an RMA on a failed drive. (ridiculous process that they do not have in place for a drive that was supplied with a NAS). So if any of your drives fail go register them under your account as an individual drive and then it “might” not take as long to RMA.

Here is the WD EX4100 product page which has the 32TB version listed.

Anyway, I just found an actual Product Compatibility page and the 10TB are compatible.