If you want full compatibility with all versions of PDF documents, then the only original PDF viewer is from the source and that is Adobe. Adobe PDF documents are universally used in business, education and personal exchanges and the documents themselves can contain very rich graphics and diagrams.
Adobe Reader XI is the standard in PDF document viewing, yet it does lack in several areas. Firstly, Adobe Reader XI can be painfully slow at times and with the awesome amount of ability it packs into one program, I suppose it isn't too abnormal that it might at times slow down. Still, there are many different free PDF readers available and many are choosing not to use Adobe.
The benefits of running Adobe PDF Reader XI are negligible compared to many of the other options, so if you must, install this program. Otherwise, take a look around for some faster programs like Foxit's free PDF reader.
Adobe Reader XI is software which can read PDF files.Features and highlights
Adobe Reader is licensed as freeware for the Windows (32-bit and 64-bit) operating system / platform from pdf software without restrictions. Adobe Reader 11.0.23 is available to all software users as a free download (Freeware).
Compatibility with this PDF viewer software may vary, but will generally run fine under Microsoft Windows 10, 8, 8.1, 7, Vista and XP on either a 32-bit or 64-bit setup. A separate x64 version may be available from Adobe. This download is distributed as AdbeRdr11000_mui_Std.zip and reader.
We have tested Adobe Reader XI 11.0.23 against malware with several different programs. We certify that this program is clean of viruses, malware and trojans.