Oops, it doesn't look like 'app update day' is a national day..

Other days

self care

Self Care Day
gum

Gum Day
my little pony

My Little Pony Day
bow tie

Bow Tie Day
prosecco

Prosecco Day
special education

Special Education Day
coffee

Coffee Day
pampering

Pampering Day
mean girls

Mean Girls Day
one

One Day