import re


def increment_version_number(last_release):
    """
    Increment the most minor non-zero part of the version number

    Args:
        last_release(str): Most recent previous release number

    Returns:
        str: Minimally incremented version number

    """
    numre = re.compile(r"\d+|[^\d]+")
    tokens = numre.findall(last_release)
    for i in reversed(range(0, len(tokens))):
        if tokens[i].isdigit():
            tokens[i] = str(int(tokens[i]) + 1)
            break
    version = "".join(tokens)
    return version