<s>
The	O
following	O
is	O
a	O
timeline	B-Operating_System
of	I-Operating_System
WhatsApp	I-Operating_System
,	O
a	O
proprietary	B-Application
cross-platform	B-Operating_System
,	O
encrypted	O
,	O
instant	B-Application
messaging	I-Application
client	O
for	O
smartphones	B-Application
.	O
</s>
<s>
Year	O
Month	O
and	O
date	O
Event	O
type	O
Details	O
2009	O
February	O
24	O
Company	O
Jan	O
Koum	O
incorporates	O
WhatsApp	B-Application
in	O
USA	O
.	O
</s>
<s>
2009	O
August	O
Product	O
WhatsApp	B-Application
2.0	O
is	O
released	O
on	O
the	O
App	B-Application
Store	I-Application
for	I-Application
the	I-Application
iPhone	I-Application
.	O
</s>
<s>
2009	O
December	O
Product	O
WhatsApp	B-Application
for	O
the	O
iPhone	O
is	O
updated	O
to	O
send	O
photos	O
.	O
</s>
<s>
2010	O
August	O
Product	O
WhatsApp	B-Application
support	O
for	O
Android	B-Application
OS	I-Application
is	O
added	O
.	O
</s>
<s>
2011	O
January	O
21	O
Competition	O
WeChat	B-Application
,	O
a	O
messenger	O
app	O
,	O
is	O
founded	O
.	O
</s>
<s>
2011	O
April	O
Funding	O
In	O
Series	O
A	O
round	O
,	O
WhatsApp	B-Application
founders	O
agree	O
to	O
take	O
$8	O
million	O
from	O
Sequoia	O
Capital	O
on	O
top	O
of	O
their	O
$	O
250,000	O
seed	O
funding	O
,	O
after	O
months	O
of	O
negotiation	O
with	O
Sequoia	O
partner	O
Jim	O
Goetz	O
.	O
</s>
<s>
2012	O
January	O
6	O
Security	O
An	O
unknown	O
hacker	O
publishes	O
a	O
website	O
that	O
makes	O
it	O
possible	O
to	O
change	O
the	O
status	O
of	O
an	O
arbitrary	O
WhatsApp	B-Application
user	O
,	O
as	O
long	O
as	O
the	O
phone	O
number	O
was	O
known	O
.	O
</s>
<s>
2012	O
August	O
Security	O
The	O
WhatsApp	B-Application
support	O
staff	O
announce	O
that	O
messages	O
were	O
encrypted	O
in	O
the	O
"	O
latest	O
version	O
"	O
of	O
the	O
WhatsApp	B-Application
software	O
for	O
iOS	O
and	O
Android	B-Application
(	O
but	O
not	O
BlackBerry	O
,	O
Windows	O
Phone	O
,	O
and	O
Symbian	O
)	O
,	O
without	O
specifying	O
the	O
cryptographic	O
method	O
.	O
</s>
<s>
2013	O
February	O
Userbase	O
WhatsApp	B-Application
's	O
user	O
base	O
swells	O
to	O
about	O
200	O
million	O
active	O
users	O
and	O
its	O
staff	O
to	O
50	O
.	O
</s>
<s>
2013	O
July	O
Funding	O
Sequoia	O
invests	O
another	O
$50	O
million	O
in	O
Series	O
B	O
round	O
,	O
valuing	O
WhatsApp	B-Application
at	O
$1.5	O
billion	O
.	O
</s>
<s>
2013	O
July	O
16	O
Product	O
WhatsApp	B-Application
goes	O
free	O
,	O
with	O
an	O
annual	O
subscription	O
fee	O
of	O
$1	O
after	O
the	O
first	O
year	O
.	O
</s>
<s>
2013	O
August	O
Competition	O
Telegram	B-Application
,	O
a	O
cloud-based	O
instant	B-Application
messaging	I-Application
service	O
,	O
launches	O
.	O
</s>
<s>
2013	O
August	O
Product	O
WhatsApp	B-Application
introduces	O
voice	O
messaging	O
.	O
</s>
<s>
2014	O
February	O
19	O
Company	O
Facebook	O
,	O
Inc	O
.	O
announces	O
its	O
acquisition	O
of	O
WhatsApp	B-Application
for	O
US$19	O
billion	O
,	O
its	O
largest	O
acquisition	O
to	O
date	O
.	O
</s>
<s>
Facebook	O
pays	O
$4	O
billion	O
in	O
cash	O
,	O
$12	O
billion	O
in	O
Facebook	O
shares	O
,	O
and	O
an	O
additional	O
$3	O
billion	O
in	O
restricted	O
stock	O
units	O
granted	O
to	O
WhatsApp	B-Application
's	O
founders	O
.	O
</s>
<s>
2014	O
March	O
Security	O
Someone	O
discovers	O
a	O
vulnerability	O
in	O
WhatsApp	B-Application
encryption	O
on	O
the	O
Android	B-Application
application	I-Application
that	O
allows	O
another	O
app	O
to	O
access	O
and	O
read	O
all	O
of	O
a	O
user	O
's	O
chat	O
conversations	O
within	O
it	O
.	O
</s>
<s>
2014	O
November	O
Product	O
WhatsApp	B-Application
introduces	O
a	O
feature	O
named	O
Read	O
Receipts	O
,	O
which	O
alerts	O
senders	O
when	O
their	O
messages	O
are	O
read	O
by	O
recipients	O
.	O
</s>
<s>
Within	O
a	O
week	O
,	O
WhatsApp	B-Application
introduces	O
an	O
update	O
allowing	O
users	O
to	O
disable	O
this	O
feature	O
so	O
that	O
message	O
recipients	O
do	O
not	O
send	O
acknowledgements	O
.	O
</s>
<s>
2015	O
January	O
21	O
Product	O
WhatsApp	B-Application
launches	O
WhatsApp	B-Application
Web	I-Application
,	O
a	O
web	O
client	O
which	O
can	O
be	O
used	O
through	O
a	O
web	O
browser	O
by	O
syncing	O
with	O
the	O
mobile	O
device	O
's	O
connection	O
.	O
</s>
<s>
2015	O
January	O
21	O
Product	O
WhatsApp	B-Application
announces	O
its	O
policy	O
on	O
cracking	O
down	O
on	O
3rd-party	O
clients	O
,	O
including	O
WhatsApp+	O
.	O
</s>
<s>
Users	O
would	O
not	O
be	O
able	O
to	O
use	O
WhatsApp	B-Application
's	O
services	O
at	O
all	O
until	O
the	O
third-party	O
apps	O
are	O
uninstalled	O
.	O
</s>
<s>
2015	O
March	O
Product	O
Added	O
voice	O
calls	O
between	O
two	O
accounts.WhatsApp	O
finally	O
adds	O
voice	O
calls	O
for	O
all	O
Android	B-Application
users	O
,	O
iOS	O
coming	O
soon	O
-	O
James	O
Vincent	O
,	O
The	O
Verge	O
,	O
31	O
March	O
2015	O
2015	O
December	O
Legal	O
WhatsApp	B-Application
is	O
briefly	O
shut	O
down	O
in	O
Brazil	O
after	O
it	O
refuses	O
to	O
place	O
wiretaps	O
on	O
certain	O
WhatsApp	B-Application
accounts	O
.	O
</s>
<s>
2016	O
January	O
18	O
Product	O
Jan	O
Koum	O
announces	O
that	O
WhatsApp	B-Application
will	O
no	O
longer	O
charge	O
its	O
users	O
a	O
$1	O
annual	O
subscription	O
fee	O
.	O
</s>
<s>
There	O
is	O
still	O
no	O
clear	O
plan	O
for	O
monetizing	O
WhatsApp	B-Application
.	O
</s>
<s>
2016	O
March	O
Legal	O
Diego	O
Dzodan	O
,	O
a	O
Facebook	O
executive	O
,	O
is	O
arrested	O
by	O
Brazilian	O
federal	O
police	O
after	O
Facebook	O
fails	O
to	O
turn	O
over	O
information	O
from	O
his	O
WhatsApp	B-Application
messaging	O
account	O
into	O
a	O
judge	O
's	O
request	O
for	O
a	O
drug	O
trafficking	O
investigation	O
.	O
</s>
<s>
2016	O
March	O
2	O
Product	O
WhatsApp	B-Application
introduces	O
its	O
document-sharing	O
feature	O
,	O
initially	O
allowing	O
users	O
to	O
share	O
PDF	O
files	O
with	O
their	O
contacts	O
.	O
</s>
<s>
2016	O
April	O
5	O
Product	O
,	O
Security	O
WhatsApp	B-Application
and	O
Open	O
Whisper	O
Systems	O
announce	O
that	O
they	O
finish	O
adding	O
end-to-end	O
encryption	O
to	O
"	O
every	O
form	O
of	O
communication	O
"	O
on	O
WhatsApp	B-Application
,	O
and	O
that	O
users	O
could	O
now	O
verify	O
each	O
other	O
's	O
keys	O
.	O
</s>
<s>
2016	O
May	O
10	O
Product	O
WhatsApp	B-Application
is	O
introduced	O
for	O
both	O
Windows	O
and	O
Mac	B-Application
operating	O
systems	O
.	O
</s>
<s>
2016	O
November	O
Product	O
Added	O
video	B-Application
calls	I-Application
between	O
two	O
accounts.WhatsApp	O
Is	O
Now	O
Rolling	O
Out	O
Video	B-Application
Calling	I-Application
For	O
iPhone	O
,	O
Android	B-Application
And	O
Windows	O
Phone	O
-	O
Amit	O
Chowdhry	O
,	O
15	O
November	O
2016	O
2017	O
September	O
5	O
Product	O
WhatsApp	B-Application
started	O
external	O
testing	O
of	O
an	O
enterprise	O
platform	O
which	O
enables	O
companies	O
to	O
provide	O
customer	O
service	O
to	O
users	O
at	O
scale	O
.	O
</s>
<s>
Airline	O
KLM	B-General_Concept
launches	O
such	O
a	O
service	O
.	O
</s>
<s>
2018	O
July	O
Product	O
Added	O
group	O
voice	O
and	O
video	B-Application
calls	I-Application
for	O
up	O
to	O
four	O
accounts.WhatsApp	O
launches	O
four-person	O
group	O
video	B-Application
calling	I-Application
-	O
Jon	O
Fingas	O
,	O
Engadget	O
,	O
30	O
July	O
2018	O
2020	O
April	O
Product	O
Group	O
calls	O
now	O
allow	O
up	O
to	O
8	O
accounts.Now	O
video	B-Application
chat	I-Application
with	O
more	O
than	O
4	O
people	O
on	O
WhatsApp	B-Application
,	O
here	O
is	O
how	O
-	O
Ankita	O
Chakravarti	O
,	O
India	O
Today	O
,	O
22	O
April	O
2020	O
2021	O
August	O
Product	O
WhatsApp	B-Application
announced	O
that	O
users	O
will	O
be	O
able	O
to	O
send	O
photos	O
and	O
videos	O
that	O
will	O
disappear	O
after	O
one	O
view	O
.	O
</s>
