How to resolve error with discrete step solver when the simulation is moved from one version to another?

Hi

I am using Plecs blockset (4.3.6) with Matlab 2019b. The model works fine both in variable-step solver and discrete step solver.

However, when I export the model from Matlab 2019b to Matlab 2017b with Plecs blockset (4.4.1) it results in an error when the model is run in discrete step solver.

“Variable-step discrete tasks are not supported with a fixed-step solver or a ‘Discrete state-space’ model”

Error screenshot is attached. I have also attached the screenshot of symmetrical PWM plecs block which results in this error. The sampling is set to regular single edge.

When I change the PWM sampling to natural the simulation runs, but the results are not as expected.

Please suggest a solution to this.

Thanks

Sneha