Nop. Unfortunately.
I just did it with success. But it was quite a long process and I didn't document it cause I new what I was doing. Here are some guide lines.
Make sure that you have php5 and MySQL5 (php.net and mysql.com both recommend upgrading to these versions. So does the a2billing team). Make sure that php have a nice set of extensions included. Here are the extension that I always activate in php (no matter what):
Code:
apache2 bzip2 ctype doc flatfile ftp gd hash imap inifile mhash mysql mysqli odbc pcntl pcre simplexml soap sockets zip
pcntl and mysql or mysqli and required for a2billing to work. But if you are working with PgSQL, than add the required extension.
Keep in mind that there are many new tables in a2billing v1.3 and for the table that are common, some of them have additional fields in v1.3 that are missing in v1.2.3 but all the fields of v1.2.3 have kept their original name in v1.3
So here is what I suggest. Install phpmyadmin or something that let you manage your db easily. Export the data (not the structure) from v1.2.3 and import in the same table in v1.3
Configure the callback-daemon if you need it
Verify the location of the log files
Make sure that you have a log rotation daemon available and configured (you will thank me for that)
Configure the cront job
etc.
Let us know about the transition.