Oh, just found out the answer myself. Seem BDO is also upgrading. Here's what it says in the news.
"The country’s largest bank said its automated teller machines (ATMs), mobile and online banking as well as debit and cash card transactions would be temporarily inaccessible to clients starting 8 p.m. on April 19 (Good Friday) to 12 noon on April 20 (Black Saturday)."
"“We are advising our clients and the general public to perform their banking transactions ahead of this scheduled activity to avoid any inconvenience,” BDO said.
The system improvement, once completed, will help BDO provide better service to its growing number of clients and offer banking convenience to even more Filipinos.
Ayala-led Bank of the Philippine Islands (BPI) is also undertaking a systems upgrade."
BDO, BPI push system upgrades | Philstar.com