Not sure if you mean Serviio running on iOS or controlling Serviio with an iPad or iPhone.
Currently you can control Serviio with Web UI on your iDevice, you can make it into web app Personally I prefer the web UI in PHP, it has iOS style controls
Sony Bravia 2010 52NX803 - Sony PS3 - Xbox 360 Serviio running on QNAP NAS 639 Pro - 1.6 Intel Dual Core - 2GB RAM and QNAP NAS 121 - 2Ghz ARM Marvell - 1GB RAM Console using ServiiDroid for Android, ServiiMetro and ServiiWP for Windows Phone and WebUI for iOS
Can you please elaborate on this issue and maybe post a screenshot? I know about a bug saving your setting having the free version. Will be fixed next week.
If I'm able to reproduce the issue, I'll try to fix it quickly.