<s>
Courier	B-Protocol
(	O
also	O
known	O
as	O
Courier	B-Protocol
Email	O
)	O
was	O
an	O
email	B-Protocol
client	I-Protocol
for	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
The	O
software	O
was	O
originally	O
released	O
in	O
1996	O
as	O
Calypso	B-Protocol
by	O
Micro	O
Computer	O
Systems	O
(	O
MCS	O
)	O
.	O
</s>
<s>
Courier	B-Protocol
supported	O
the	O
POP3	B-Protocol
,	O
IMAP	B-Protocol
and	O
SMTP	B-Protocol
protocols	I-Protocol
,	O
provided	O
several	O
features	O
for	O
HTML	O
security	O
and	O
allowed	O
to	O
use	O
multiple	O
e-mail	O
accounts	O
from	O
one	O
mailbox	O
.	O
</s>
<s>
In	O
1998	O
the	O
MCS	O
introduced	O
another	O
Calypso	B-Protocol
branded	O
product	O
,	O
Calypso	B-Protocol
Message	O
Center	O
,	O
intended	O
for	O
tracking	O
and	O
distributing	O
messages	O
for	O
corporate	O
customers	O
.	O
</s>
<s>
The	O
company	O
abandoned	O
further	O
development	O
of	O
Calypso	B-Protocol
,	O
which	O
was	O
acquired	O
in	O
2003	O
by	O
RoseCitySoftware	O
.	O
</s>
<s>
This	O
led	O
to	O
freeware	O
release	O
of	O
version	O
3.3	O
and	O
name	O
change	O
of	O
the	O
next	O
shareware	O
version	O
3.5	O
to	O
Courier	B-Protocol
.	O
</s>
<s>
An	O
upgrade	O
path	O
was	O
negotiated	O
with	O
PocoSystems	O
to	O
add	O
Courier-type	O
features	O
to	O
Pocomail	B-Application
and	O
direct	O
Courier	B-Protocol
users	O
to	O
migrate	O
to	O
PocoMail	B-Application
4.8	O
as	O
a	O
replacement	O
for	O
Courier	B-Protocol
3.5	O
.	O
</s>
<s>
Free	O
versions	O
of	O
the	O
unfinished	O
beta	O
,	O
requiring	O
no	O
registration	O
,	O
were	O
available	O
at	O
the	O
Yahoo	O
Courier	B-Protocol
user	O
group	O
.	O
</s>
