Replacing RPI 2 with RPI 3

I currently run a RPI 2 with aurdino for my brewpi. I also have a RPI 3 that I would like to switch over to. Do I have to reinstall completely on the RP3 or can I just switch SD cards.

If your RPI2 is not using Jessie, you will have to reinstall.

I am using wheezy. I was told legacy could not be used on Jessie with Pi and Audrino . Has this changed?

I’m currently using Jessie on RPI3 and Arduino (MultichanberSetup). What I had to do was adjust the install to switch to using the legacy branch for the arduino to work. Also had to manually flash the hex file to the arduino, then once setup I had to set the arduino to factor defaults in the Maintenance panel. To switch to legacy branch you will need to use sudo python --ask. If you like, I can share my image file I saved after getting things configured on jessie for RPI3 and multi chamber support.

sudo apt-get update
git clone ~/brewpi-tools
sudo python ~/brew-tools/ --ask

Select Legacy and point to /home/brewpi/conical#
Select Legacey and point to /var/www/html/conical#

For rpi2 I used wheezy then used legacy and manually installed hex onto Audrino too. So I think it would be same setup just this time i install Jessie and make sure again I use legacy. And also I think the www folder structure changed.

Is it work switching from rpi2 to 3 for this project or is there no difference in performance of brewpi with 2 vs 3

I would assume, if using a single chamber/conical, you’d not see any difference. I only have a RPI3 and I’m using it for multiple conical and it performs well.