Veterans Appeals Improvement and Modernization Act of 2017 This bill revises the Department of Veterans Affairs (VA) disability claims appeals system. The bill permits a veteran to appeal within one year by: (1) requesting a review of the agency of original jurisdiction's (AOJ) decision by a higher-level adjudicator within AOJ using the same evidentiary record; (2) filing a supplemental claim with a regional office that includes the opportunity to submit additional evidence and have a hearing; or (3) appealing directly to the Board of Veterans' Appeals, with the opportunity to select an expedited review to submit new evidence but without a hearing, or to select a review with the option to submit new evidence and request a hearing. A veteran may: (1) maintain the original effective date of a claim if he or she submits new and relevant evidence within one year of the most recent decision, and (2) retain the services of attorneys and accredited agents who charge a fee when the AOJ provides notice of the original decision. The VA's statutory duty to assist a veteran terminates after the original decision. The bill: (1) requires the VA to issue decision notification letters, (2) permits certain veterans who initiated an appeal prior to the bill's effective date to opt-in to the modernized appeals system, (3) authorizes the VA to conduct a pilot program to test such system, and (4) requires the VA, prior to full implementation, to certify to Congress that it has sufficient resources and personnel to carry out the legacy and modernized appeals systems.