No it won't run 4.1.3. However, Sun will provide you with a copy Solaris1.1C(4.1.3C) which will allow you to run "4.1.3" on a LX or Classic. These machines can also run 4.1.3_U1 and 4.1.4. See Question 61 for more details. The cost is around $125 for the media and $100 for the RTU license. Users of 4.1.3C should get the DBRI patch if you don't have a speaker box!