What is recommend method for OS7 beta experience

Most OS5 X64(but N7700PROV2/N8800PROV2) should work with OS7 for beta testing, OS5 X64 system have different file structure, ACL and others, thus have no plan to support OS5 upgrade/migrate to OS7 officially. If went migrate to OS7 for beta experience, it is strong recommend backup current data first, then create new RAID volume from OS7, and following steps for your reference:

(!!Please note this method unable roll back to OS5!! Please double confirm before this operation!)
(If you just went to doing some preview & testing, please refer to following link:
http://thecus.kayako.com/default_import/Knowledgebase/Article/View/644/0/how-to-update-to-os7-beta-for-evaluation-n2800-n4800eco-n5550-n7510-and-n5810)

1. Confirm all your data been backup already and update to OS7.*1 *2
2. Power OS7 NAS up without HDD.
3. Login into OS7 ADMIN WEB interface page, load factory default and reboot.
4. Login into OS7 ADMIN WEB interface page, hot plug HDD into NAS.
5. Create new RAID volume from OS7.

*1
Following OS5 X64 NAS models have capability to support OS but N7700PROV2/N8800PROV2.

http://ftp2.thecus.com/~thecus/download/AutoUpgrade/THECUS/Thecus_x86_64_FW.3.02.02
N16850 Series
N16000 Series
N12850 Series
N12000 Series
N8900 Series
TopTower N10850
TopTower N8850
TopTower N6850
N8880-10G
N8810U Series
N7770-10G
N7710 Series
N5810 Series (certain early version is OS5 V2.x.x, OS7 start from V3.x.x)

http://ftp2.thecus.com/~thecus/download/AutoUpgrade/THECUS/Thecus_x86_64_FW.3.02.02.cdv
N7510 Series
N5550
N4800 Series
N4510U
N2800

*2
A. If you observe any issues or inconsistencies, please address these via the Feedback button in ThecusOS 7.0 for os7@thecus.com.
B. Thecus is not responsible for any data loss or damage during the Beta Program. Individuals are strongly advised to backup all data before beginning.
C. Thecus is not responsible for an any issues or damages to your product during the Beta Program.
D. Please note that, as this is a Beta version and not a formal release, you may experience errors or inaccuracies that may cause data loss and other system issues. Some features may also not be fully functional. If these events do occur, you may need to reinitialize your system.