Everything so far (limited testing) has worked on Android phones, iPads, Iphones and PCs [both filr client and web for PC; apps for other devices].

We are a rather small organization so purchasing an SSL cert doesn't make much sense. I couldn't get two Windows phones (7.5 and 8) to ever load the filr login page. No errors, it just kept trying to load the page in IE. I loaded UC Browser to see if the problem was IE. UC Browser gave an error that the website was unavailable.

I did some digging and found this to work on both versions of Windows phone tested:

My self signed cert matches the FQDN of my filr server - I believe it is key to this working at all.

First you must install the self signed certificate to the PC you are using.

Open the mmc and load the snap-in for Certificates, select Local computer;
- on Trusted Root Certification Authorities - Certificates
- Search for the certificate
- export this certificate as a DER-coded-binary X.509 (CER) on the local Computer

- Send the certificate via e-Mail to an account available on the Windows phone

- Sync the phone Mail Box and open the attachment

- install the certificate to the phone

I was then able to load the page and login to filr.