Compared to the latest data of DR8 v2.0, there are three major changes in DR9 v1.1 as follows.

1.  The fields of "tfrom", "tcomment", and "tsource" were deleted from all LAMOST low and medium resolution catalogs except the "LAMOST LRS Input Catalog" and "LAMOST MRS Input Catalog".

2.  At the end of the "LAMOST MRS General Catalog", a new field of "subproject" was added to provide the sub-project names of LAMOST Medium-Resolution Spectroscopic Survey, which was detailedly introduced in the last but one paragraph of subsection 3.1 in the low/medium resolution data description.

3. At the end of "LAMOST LRS Catalog of Cataclysmic Variable stars", three new fields were added, and they are "r", "abs_gmag", and "abs_gmag_err", which were detailed introduced in the low resolution data description.