Leaving the District: Pack your IEP and take it with you!
Under federal law, your new school district must honor and implement a current IEP. This means that the new school district must put in place the same or comparable services that your child was given in the previous school district.
Do go on the school district website and familiarize yourself with its special education department and the services and information that it provides. Don't wait to ask for a meeting: the special education director should be around during the summer. Join the Special Education Parent Advisory Counsel; email the parent leaders and ask for some local "navigation" tips.
Each state has its own special education laws and regulations: those laws implement the federal laws, and can offer additional protections to children beyond those provided under federal law. However, the state cannot take away protections given under federal law. So, if you receive any push back from your new district, don't take it! If they say look at your child's IEP and say "we don't do that here," then they must offer you something substantially the same or equivalent. If the school district tells you that it will be "months" to get the IEP in place, don't accept that either: the law does not allow the school to wait to implement the services.
Unfortunately, it is not uncommon for the school districts to delay in sending records to the new school, even when requested. This may make it difficult for the new school to get up to speed quickly on your child's needs. It is smart to get a copy of your child's records before you move: you can give them to the new school yourself.