<s>
In	O
software	B-Application
development	O
,	O
when	O
software	B-Application
has	O
been	O
forked	B-Application
or	O
uses	O
a	O
chain	O
of	O
libraries/dependencies	O
,	O
upstream	B-General_Concept
refers	O
to	O
an	O
issue	O
that	O
occurs	O
in	O
software	B-Application
farther	O
up	O
the	O
chain	O
.	O
</s>
<s>
It	O
is	O
the	O
direction	O
that	O
is	O
toward	O
the	O
original	B-General_Concept
authors	I-General_Concept
or	O
maintainers	B-General_Concept
of	O
software	B-Application
.	I-Application
</s>
<s>
It	O
is	O
usually	O
used	O
in	O
the	O
context	O
of	O
a	O
version	O
,	O
a	O
bug	B-Error_Name
,	O
or	O
a	O
patch	O
.	O
</s>
<s>
Upstream	B-General_Concept
development	O
allows	O
other	O
distributions	O
to	O
benefit	O
from	O
it	O
when	O
they	O
pick	O
up	O
the	O
future	O
release	O
or	O
merge	O
recent	O
(	O
or	O
all	O
)	O
upstream	B-General_Concept
patches	O
.	O
</s>
<s>
Likewise	O
,	O
the	O
original	B-General_Concept
authors	I-General_Concept
(	O
maintaining	O
upstream	B-General_Concept
)	O
can	O
benefit	O
from	O
contributions	O
that	O
originate	O
from	O
custom	O
distributions	O
,	O
if	O
their	O
users	O
send	O
patches	O
upstream	B-General_Concept
.	O
</s>
<s>
The	O
term	O
also	O
pertains	O
to	O
bugs	B-Error_Name
;	O
responsibility	O
for	O
a	O
bug	B-Error_Name
is	O
said	O
to	O
lie	O
upstream	B-General_Concept
when	O
it	O
is	O
not	O
caused	O
through	O
the	O
distribution	B-Application
's	O
porting	O
,	O
non-upstream	O
modification	O
or	O
integration	O
efforts	O
.	O
</s>
<s>
A	O
patch	O
sent	O
upstream	B-General_Concept
is	O
offered	O
to	O
the	O
original	B-General_Concept
authors	I-General_Concept
or	O
maintainers	B-General_Concept
of	O
the	B-Application
software	I-Application
.	O
</s>
<s>
If	O
accepted	O
,	O
the	O
authors	O
or	O
maintainers	B-General_Concept
will	O
include	O
the	O
patch	O
in	O
their	O
software	B-Application
,	O
either	O
immediately	O
or	O
in	O
a	O
future	O
release	O
.	O
</s>
<s>
If	O
rejected	O
,	O
the	O
person	O
who	O
submitted	O
the	O
patch	O
will	O
have	O
to	O
maintain	O
his	O
or	O
her	O
own	O
distribution	B-Application
of	O
the	O
author	O
's	O
software	B-Application
.	I-Application
</s>
<s>
Upstream	B-General_Concept
repository	O
or	O
source	O
code	O
distribution	B-Application
version	O
,	O
which	O
can	O
either	O
be	O
a	O
version-tagged	O
release	O
for	O
which	O
the	O
source	O
code	O
has	O
specifically	O
been	O
packaged	O
,	O
a	O
specific	O
commit	O
,	O
or	O
master	O
(	O
jargon	O
for	O
latest	O
commit	O
)	O
.	O
</s>
<s>
Where	O
custom	O
distributions	O
(	O
such	O
as	O
forks	B-Application
)	O
may	O
have	O
missed	O
out	O
on	O
bugfixes	O
and	O
improvements	O
(	O
maturing	O
of	O
the	O
project	O
tied	O
to	O
the	O
original	B-General_Concept
authors	I-General_Concept
,	O
upstream	B-General_Concept
)	O
as	O
a	O
result	O
of	O
not	O
merging	O
(	O
all	O
)	O
upstream	B-General_Concept
patches	O
.	O
</s>
<s>
In	O
such	O
cases	O
,	O
the	O
custom	O
distribution	B-Application
may	O
even	O
have	O
been	O
adapted	O
to	O
suit	O
the	O
specific	O
needs	O
and	O
requirements	O
of	O
those	O
using	O
or	O
maintaining	O
it	O
.	O
</s>
<s>
This	O
is	O
also	O
often	O
seen	O
with	O
dependencies	B-Application
(	O
vendor	O
packages	O
)	O
,	O
where	O
the	O
taker	O
just	O
settles	O
with	O
a	O
base	O
version	O
once	O
and	O
tends	O
to	O
stick	O
with	O
it	O
,	O
over	O
time	O
accumulating	O
so	O
many	O
(	O
arbitrary	O
)	O
modifications	O
or	O
non-standard	O
uses	O
in	O
their	O
environment	O
that	O
merging	O
the	O
latest	O
upstream	B-General_Concept
patches	O
into	O
their	O
custom	O
distribution	B-Application
wo	O
n't	O
be	O
possible	O
without	O
major	O
additional	O
work	O
for	O
patch	O
and	O
feature	O
compatibility	O
,	O
and	O
avoiding	O
duplicate	O
patches	O
of	O
bugs	B-Error_Name
that	O
they	O
resolved	O
by	O
themselves	O
(	O
and	O
in	O
their	O
own	O
way	O
)	O
while	O
upstream	B-General_Concept
also	O
has	O
a	O
patch	O
for	O
it	O
.	O
</s>
<s>
A	O
lot	O
of	O
custom	O
distribution	B-Application
users	O
would	O
still	O
cherry-pick	O
and	O
merge	O
critical	O
upstream	B-General_Concept
patches	O
(	O
such	O
as	O
security	O
vulnerability	O
related	O
)	O
.	O
</s>
