Reactive state engine problem "Can't use sequence sensitive function next" and "steps must be positive integer" when using move(x,-1).

example code is as under:

metrics1=<iif(ts>next(ts),1,NULL)>

When using this code engine gives error "Can't use sequence sensitive function next"

I modified the code with move as under:

metrics1=<iif(ts>move(ts,-1),1,NULL)>

Then it gives an error "Steps must be a positive integer"

Please solve the problem as soon as possible.

Thanks & regards,

Vishvesh Upadhyay