The format was already post-2.3.x.
#LyX 2.4 created this file. For more info see https://www.lyx.org/
-\lyxformat 574
+\lyxformat 589
\begin_document
\begin_header
\save_transient_properties false
\font_default_family default
\use_non_tex_fonts false
\font_sc false
-\font_osf false
+\font_roman_osf false
+\font_sans_osf false
+\font_typewriter_osf false
\font_sf_scale 100 100
\font_tt_scale 100 100
\use_microtype false
\justification true
\use_refstyle 0
\use_minted 0
+\use_lineno 0
\notefontcolor #0000ff
\index 索引
\shortcut idx