Hi,

It's going to be quite tricky to manually create a package, but it can be done. A package file is a ZIP that essentially consists of all the necessary files required for the package to work (no directories) along with an XML file (package.xml) that describes the destination of the files, package info, document types, actions, and so on. The XML would look something like this;

<umbPackage>
 <files>
   <file>
     <guid>My.Example.dll</guid>
     <orgPath>~/bin</orgPath>
     <orgName>My.Example.dll</orgName>
   <file>
   ...
 <info>
  <package>
    <name>Package name</name>
    <version>1.0.0</version>
    ...
   </package>
 </info>
 </umbPackage>

Check this out for a full example: https://our.umbraco.com/documentation/extending/Packages/Creating-a-Package/

As for whether it would work for Umbraco 8, it's really circumstantial and depends on the package. I would say most complex packages will have some teething issues after the major update, but the only want to know is to give it a go!

Good luck

The best way to create a package is using the back office, but as you've said that you can't do that, then the only way I can think of is to create the package.xml file manually in notepad (for example).

It's going to take some time, but in the example from above, you can see the structure of the package.xml. Once you have that, you just need to make a ZIP file with all the files (no directories) and the package.xml.

It's quite cumbersome to do it this way. Are you sure there is no way you can get into back office? Perhaps you can create a new Umbraco CMS 7.7 installation, copy over the App_Plugins folder (which I assume contains your package) and then try and create a new package from back office that way?

All the best

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