Troubleshooting

 Cannot install jUpgradePro v3.8 package in my Joomla! installation.

The jUpgradePro package has included lot of libraries that need to work properly and the size of the package is 23 megabytes. Some web servers configuration has the upload limit below this size so we need to adjust this.

https://stackoverflow.com/questions/2184513/change-the-maximum-upload-file-size#2184541

 Fatal error:  Allowed memory size of 256 bytes exhausted

If your ISP has in their PHP configurations a memory limit below 256 megabytes probably will to receive this error. To get jUpgradePro working you must to download the vendor.zip package available in the Downloads section and decompress it into the jUpgradePro component folder:

JOOMLA_ROOT/administrator/components/com_jupgradepro/vendor