We reverse the revocation of appellant’s probation for failing to submit monthly written reports by mail. The evidence was that he had faxed at least several months of reports. The probation officer explained that the mail-in requirement was necessary so that a probationer’s address could be verified by a postmark. With a fax, the location of the sender can be verified by an area code. The conditions of probation did not expressly prohibit faxes. The probation officer had explained to appellant the procedure for mailing in reports. However, there was no evidence that he was told that faxes were prohibited. Based on the testimony at the hearing, under the circumstances of the case there was no willful violation of probation.