### What changes were proposed in this pull request?
https://celeborn.apache.org/docs/latest/developers/overview/
> For more details, please refer to Rolling upgrade
### Why are the changes needed?
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
Closes#1927 from cxzl25/CELEBORN-997.
Authored-by: sychen <sychen@ctrip.com>
Signed-off-by: mingji <fengmingxiao.fmx@alibaba-inc.com>
### What changes were proposed in this pull request?
Fix a broken link in docs/developers/overview.md.
### Why are the changes needed?
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Locally tested.
Closes#1845 from zhouyifan279/upgrade-page-link.
Authored-by: zhouyifan279 <zhouyifan279@gmail.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>
### What changes were proposed in this pull request?
As title
### Why are the changes needed?
As title
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Manual test
Closes#1795 from cfmcgrady/sbt-docs.
Authored-by: Fu Chen <cfmcgrady@gmail.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>
### What changes were proposed in this pull request?
As title.
### Why are the changes needed?
As title
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
No.
Closes#1747 from waitinfuture/824.
Authored-by: zky.zhoukeyong <zky.zhoukeyong@alibaba-inc.com>
Signed-off-by: zky.zhoukeyong <zky.zhoukeyong@alibaba-inc.com>
### What changes were proposed in this pull request?
As title.
### Why are the changes needed?
As title.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
No.
Closes#1746 from waitinfuture/823.
Authored-by: zky.zhoukeyong <zky.zhoukeyong@alibaba-inc.com>
Signed-off-by: zky.zhoukeyong <zky.zhoukeyong@alibaba-inc.com>
