Assegnate 4 su 5 stelle

value for strict_max_version of extension's manifest.json is not set properly (set to 102.0)
works fine for me with some edits:
1. download sieve-0.6.1-tb.xpi manually
2. unzip the file to different directory
3. change value to "102.*"
4. zip again and manually install

for linux users:

cd <into directory with downloaded file>
mkdir sieve-0.6.1-tb; cd sieve-0.6.1-tb; unzip ../sieve-0.6.1-tb.xpi
sed -i 's!"strict_max_version" : "102.0"!"strict_max_version" : "102.*"!g' manifest.json
zip -r ../sieve-0.6.1-tb_edited.xpi ./

Manually installation from file via thunderbird addons tab.

:-)