Currently some 3rd party software suites still only allow importing of LAS version 1.2, by default True View EVO encodes LAS in version 1.4
You will be unable to downgrade LAS 1.4 file to 1.2 in the export dialog. This is due to the fact that LAS 1.4 is formatted in a specific way and contains additional information that LAS 1.2 spec does not. If the data were converted, EVO would have to make some potentially compromising determinations about what descriptors to keep and which ones to eliminate. By default, we prevent the user from downgrading so that the data is not negatively affected.
The current workaround for this issue is to export the point cloud as ASCII XYZ and then reimport it as LAS 1.2 using the File -> Import ASCII XYZ. During the export be sure the check what ever attributes (RBG, classification etc.) you need.