Thanks, Jan. I wanted to make you all aware if you are not already that our 10-K was filed with the SEC this morning. Now I'll review some important developments and then discuss our Q4 and full year results, after which we'll open the call to investor questions.
In 2023, particularly in the latter half of the year, we completed some significant initiatives that we've been working on for quite some time. First of all, we've been developing a new user interface for our OmniView customer data portal since 2021. After a lengthy period of planning and development, OmniView 2.0 or OV 2, as we call it, became available to customers as of October 1, 2023, in beta mode. OV 2.0 provides a range of new features, including a new more aesthetically appealing and modern user interface, self-service run reporting and access to air quality data to support regulatory compliance for our customers.
Overall, OV 2.0 provides more functionality and a more modern design that delivers a much better user experience. We're very excited about the launch of OV 2.0. We'll be rolling that out to all customers on or about March 18. The customer response has been excellent, making us feel that OV 2.0 extends our competitive edge and should keep us ahead of our competition in 2024 and moving forward.
Also on September 1, 2023, we launched updated versions of our TrueGuard, AirGuard, Patriot and Hero products that include new functionality relating to how our customers are able to access and utilize data provided by these devices. The new version of our products allows our customers to have the option to purchase our monitoring service to monitor the products themselves that they have that capability or to choose another monitoring provider.
Historically, our products only worked with our monitoring services. This new functionality results in OmniMetrix hardware and monitoring services being treated as 2 distinct offerings. As a result, revenue, cost of goods and related commissions on sales of the updated hardware devices are recognized upon product shipment rather than deferred and amortized over the estimated life of the unit, which had historically been 3 years as was the case with sales of the prior version of our hardware. Revenue recognition for monitoring services is still amortized ratably over the term of the service contract, which is typically 1 year.
Turning to our 2023 results. Full year revenue rose 15% to $8.1 million with hardware revenue increasing 23% and monitoring revenue rising 9%. The increase in hardware revenue was driven by $475,000 in sales of our new product versions, which was not deferred and $259,000 from sales of custom design units from one C&I customer.
As Jan mentioned, monitoring revenue returned to growth in 2023 following a decrease in monitoring endpoints in 2022, driven by mobile carriers sunsetting of 3G technology, which impacted legacy 3G monitoring hardware. Q4 '23 revenue increased 22% to $2.25 million, driven by a 37% increase in hardware revenue and a 9% increase in monitoring revenue. The increase in revenue in the fourth quarter of '23 was due to the same drivers as the increase for the full year.
Gross profit grew 18% to $6 million in 2023, reflecting both revenue growth and margin improvements. Our gross profit margin improved to 74.5% versus 72.4% in 2022, primarily due to an increase in hardware gross margin to 54% from 48% in 2022. The hardware margin improvement reflects sales of higher-value new products and custom units, which tend to sell at higher price points. Q4 gross profit rose 22% to $1.6 million, in line with revenue growth.
Total operating expenses, including $102,000 of expenses related to our 1-for-16 reverse stock split increased 4% or $230,000 to $5.9 million in 2023. Excluding onetime reverse stock split expenses, total operating expenses would have increased only 2% versus 2022.
Q4 '23 total operating expenses increased 10% or $143,000 to $1.6 million, including a $90,000 increase in SG&A and a $53,000 increase in R&D both primarily reflecting increases in personnel-related expenses, namely salaries and bonuses. Additionally, we've expanded our IT department, upgraded our software development skill sets and invested in our cybersecurity plan, which we will continue to execute into 2024.
Net income attributable to stockholders improved to $119,000 or $0.05 per share in 2023 from a net loss of $633,000 or 25% -- $0.25 per share in 2022. This includes $0.04 per share for expenses related to our reverse stock split in 2023. Note that per share figures are adjusted to reflect the 1-for-16 reverse stock split.
Q4 '23 net income attributable to shareholders improved to $84,000 or $0.03 per share from a net loss of $77,000 or $0.03 per share in Q4 '22. The swing to profitability was driven by revenue and gross profit growth that exceeded operating expense increases. Acorn generated $72,000 of cash from operating activities in 2023, mainly attributable to our net income plus noncash expenses, less investments in operating assets and liabilities, including working capital. We used $78,000 for hardware, software and other capital investments during the year, mainly for the residual investment in OV 2.0.
Looking at our balance sheet, Acorn had consolidated cash of $1.45 million at December 31, 2023, and approximately $1.24 million on March 5, 2024, as compared to $1.45 million at December 31, 2022. The company also had no outstanding debt in these periods. Inventory increased to $962,000 at December 31, 2023, versus $789,000 at December 31, 2022. We invested in inventory in 2023 in order to support our growth objectives and to position the company to fulfill potentially large volume orders heading into 2024. We continue to strongly believe that our business model and financial position will facilitate the execution of our growth strategy in 2024 and longer term. I look forward to updating you on our progress in the coming months.
Operator now let's proceed to the Q&A session.