<div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="margin:0;">Dear ubuntu-devel-discuss,</div><div style="margin:0;">          I have questions about how to choice or decide which Upstream version to use for a certain software in Ubuntu Derived series.  </div><div style="margin:0;">is there some guiding principle or refer documents. <span style="color: rgb(35, 38, 41); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI Adjusted", "Segoe UI", "Liberation Sans", sans-serif; font-size: 15px;">i.e.,why choice gcc-9.3.0 in the Focal Fossa. </span></div><div style="margin:0;">                                                                                                                                                                thanks.</div><div style="margin:0;">                    </div></div>