The BIR has issued Revenue Regulations 12-2020 and 11-2020 wherein RR 12-2020 state that the defined deadlines in RR 11-2020 shall remain in effect regardless of any extension or modification of quarantine.
Why? because since the Enhanced Community Quarantine (ECQ) there were little tax-money which enters to the government and our country is in dire need of funds to re-build.
Following are the summarized Tax-deadlines:



See the following item numbers in RR 11-2020 for easy reference:
- Item 6 - 2550Q and SLS/P/I (VAT Relief)
- Item 13 - 1702Q
- Item 20 - 1600
- Item 22 - 1601C
- Item 25 - 1701/1701A/1700
- Item 26 - 1702RT/1702MX/1702EX
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Item 35 - 2551Q
-
Item 37 - 1601EQ/1601FQ/1602Q/1603Q
- Item 38 - QAP
- Item 41 - 0619E/0619F
- Item 47 - 1701Q
Here's the link for RR 11-2020:
https://www.bir.gov.ph/images/bir_files/internal_communications_1/Full%20Text%20RR%202020/Revenue%20Regulations%20No%2011-2020.pdf
For the no further extension (per RR 12-2020):
https://www.bir.gov.ph/images/bir_files/internal_communications_1/Full%20Text%20RR%202020/Revenue%20Regulations%20No.%2012-2020.pdf