I understand that you want to know if is there any issue to be aware of if you change your AV source.
It depends. First, I recommend you to verify if your new DVR is included on the supported devices list. This link will allow you to check it out:
If you are not able to find the specific model number, I encourage you to test all the IR codes from the same device manufacturer. If it does not work, you can check the following thread provided by alanrichey42.