Just tried the nightly build setup script on a copy of our 1_1 database. It
fails with a "duplicate field error. Upgrading to 1_2 first and then to 1_3
works without any hickups :-)

After the introductory message the page with the list of upgrade actions is shown:

Module 	Necessary action
email_template 	Install
scheduler 	Install
quotation 	Install
docmanager 	Install
crm 	Install
employee 	16 patches
person 	4 patches
timereg 	10 patches
project 	15 patches
organization 	14 patches
todo 	2 patches
pim 	2 patches

Please click the 'continue' button below to start the update.

After clicking continue the following error is shown:

Critical: Unknown error: 1060 (Duplicate column name 'period').
Halted
error: [+1.85701s / 0.01933s] Unknown error: 1060 (Duplicate column name 'period')
Halted...