Key Pointers –

• DRC-01B will send if there is a difference between the liability declared in GSTR-1/IFF and that paid through GSTR-3B/3BQ beyond the configurable threshold limit.
• The intimation along with the reference number will receive via email and SMS. It is also available In GST portal
• Once the DRC-01B is received then the reply should be submitted in Form DRC-01B Part B. 
• Form DRC-01B Part B can be filed either on a monthly or quarterly basis, depending on the frequency of filing GSTR-3B.
• Form DRC-01B is applicable to regular taxpayers (including SEZ units and SEZ developers), casual taxpayers, and taxpayers who have opted in or opted out of the composition scheme.
• If a taxpayer doesn’t file response to Form GST DRC-01B for previous tax period, then for the subsequent tax period, they will not be able to file their Form GSTR-1/IFF.
• After filing the reply for DRC-01B Part B, GSTR-1/IFF can be filed immediately. 
• While filing the reply for DRC-01B Part B, ensure the ARN is valid and corresponds to the same DRC-03 and GSTIN.
• The DRC-03 should be filed on or after the date when DRC-01B Part A was issued.
• Confirm that the cause of payment specified in the DRC-03 is "Liability mismatch - GSTR- 1 to GSTR-3B."
• The overall tax period should align with the period for which DRC-01B Part A was issued.
• For monthly filers, the period should be the same, including both the "From" and "To" dates.
• For quarterly filers, it should cover at least one month within the quarter.
• The detailed steps to file the DRC -1B part B are also provided in the FAQ.

Need for GST in India