<s>
Postbox	B-Protocol
is	O
a	O
desktop	O
email	B-Protocol
client	I-Protocol
,	O
news	B-Protocol
client	I-Protocol
and	O
feed	B-Application
reader	I-Application
for	O
Windows	O
and	O
macOS	B-Application
.	O
</s>
<s>
Written	O
and	O
sold	O
by	O
Postbox	B-Protocol
,	O
Inc.	O
,	O
it	O
was	O
launched	O
at	O
the	O
TechCrunch	O
50	O
conference	O
in	O
2008	O
.	O
</s>
<s>
Postbox	B-Protocol
was	O
founded	O
and	O
staffed	O
by	O
several	O
former	O
developers	O
from	O
Mozilla	B-Operating_System
.	O
</s>
<s>
The	O
software	O
was	O
built	O
using	O
Mozilla	B-Operating_System
's	O
Gecko	B-Language
browser	O
engine	O
,	O
and	O
was	O
initially	O
based	O
on	O
Thunderbird	B-Application
,	O
Mozilla	B-Operating_System
's	O
own	O
e-mail	O
software	O
.	O
</s>
<s>
Postbox	B-Protocol
7	O
requires	O
8GB	O
of	O
RAM	O
,	O
200	O
MB	O
of	O
hard	O
drive	O
space	O
,	O
plus	O
Windows	O
8	O
(	O
or	O
later	O
)	O
or	O
macOS	B-Application
10.13	O
(	O
or	O
later	O
)	O
.	O
</s>
