Today I tried to create a new piston in CORE but after click on the “if” portion then next screen is just blank. Any idea on what is happening and how to fix?
There was an update to CoRE last week that resolved this issue. Go to IDE and update the smartapp. Also consider migrating to webcore 
Could you tell me how to update and if that will affect my existing pistons?
I have considered migrating to webcore but I have about 50 core pistons. Is there a way to migrate them without having to write one by one again in webcore?
If you have a github account and linked to the smartapp in IDE, you only need to click on update from repo in the smartapp section. If you do not have a github account, you can edit the smartapp and copy/paste the new code over the old code and save/publish. Either method of updating will not cause you to lose your existing pistons.
there is no migration tool to move your pistons from core to webcore. I would suggest starting with the simple pistons first and see how webcore works. The installation guide and videos can can found on the webcore forum at https://community.webcore.co and their wiki page https://wiki.webcore.co/
A user account is required for their forum.
https://community.smartthings.com/t/webcore-forum-username-policy-verification/136055
You can find many example pistons on the webcore community forum and you can post any and all questions that you may have over there. The folks love to assist and enjoy helping with building pistons 
Normally I use the copy-paste method directly in Smartthings but I could not find the new CORE code but I found it in GitHub thanks to you.
I have some pistons already running in WebCore but I have found that it runs slower than than CORE. For example, same piston logic will turn on lights maybe 1 or 2 seconds later than what CORE does and besides this all programming needs to be done in the computer rather than in the app directly and normally I create my pistons in my free time when I do not have a computer. Thanks for the help @jkp
Hello!
I’m having this issue now. I didn’t even know this was updated.
Problem is, I cannot find were to get the updated code.
Sorry… after posting this, I actually found it.
Everything is working now.
Thank you!