After the recent "greendick" spammer attack on the steem blockchain a security fix has been released. it is recommended that all witnesses upgrade to prevent further attacks.
If you are using 
./run.sh install
after it has finished installing type :
./run.sh restart
If you have a backup server test on there first.
someguy123's upgrade post :
https://steemit.com/witness-update/@someguy123/important-update-steem-in-a-box-for-v0-19-3-steemfeed-js-update
Steem 0.19.3 github download page
https://github.com/steemit/steem/releases/tag/v0.19.3
Steem Equality 0.19.3 Release Notes
We recommend all witnesses and seed nodes update to 0.19.3
Reindexing
0.19.3 does not require reindexing when upgrading from 0.19.2
Overview
This is a cumulative security release.
Security Fixes
Previously fixed, but not contained in a tagged release, is a fix for an I/O vulnerability that could lead to a denial of service attack on nodes.
Added mitigations regarding bandwidth for custom operations, exploitation of which could lead to minor network instability, resulting in high block latency and the missing of blocks by witnesses.
server specs
64 GB RAM
Intel i7
2x2 TB HDD
1gbit/s network
current witness position : 145 (107 active rank)
Total missed blocks : 21
block size 65536
account creation fee 0.100 STEEM
running v 0.19.3
using 
Please vote pcste for witness.
to vote for me go to : https://steemit.com/~witnesses scroll down the page and enter pcste into the box (dont use 
