Sections 4391, 4395, 4396, 4397, 4398, and 4400 of the Compiled Statutes of Idaho, section 4390 as amended by House Bill 29; passed at this session of the legislature, and sections 4392, 4393, 4394 and 4401, as amended by this act, shall not apply to assessments levied in the year 1925 and subsequent years, but shall be continued in force and effect for the purpose of proceedings under any assessments levied prior to the year 1925.