BlazeMeter will always support the latest JMeter version - as well as past JMeter versions. You should use the JMeter version on your local computer to create your test scripts.
JMeter Versions Supported by BlazeMeter
Here's a list of the JMeter versions supported by BlazeMeter, which can selected on the "JMeter Version" drop down.
- 2.12 BlazeMeter
- 2.11 BlazeMeter